Alright, I've spent some time mulling over this, and even though it's doubtful Bob (or many other people at all) will read this, I figured I'd toss it out there. Some of this covers ground I've gone over before.
For starters, all of this stuff about the horrors of the white man oppressing the black man is pretty much bull. Yes, in the last few centuries we saw a brief period of time where this was the case. Throughout most of human history though, that was hardly the case. As I'm sure many people might remember from their world history classes, human civilization largely started with "The Fertile Crescent". The people that lived there? Not whites.
In the overall scheme of things white guys were pretty much the primitive savages that were running around in hides, swining from trees, and living in caves. You know, the stereotype certain racists make about darker skinned peoples. If we showed up in civilization at all, it was usually as slaves. The lighter skinned peoples in the region, like the hebrews, wound up being enslaved by the Egyptians.
I'm being intentionally brief but power shifted over a long period of time. We had the rise of the greeks who fought off attempts to enslave them en-masse (movies like 300 are overblown depictions loosely based on real events), and then the romans, but of course those people were generally dusky or olive skinned, us white guys were getting conquered and enslaved left and right by the roman empire that stomped all over Europe. Rome wound up falling, and then out of the dark ages the white guys arose finally carrying the torch of civilization that we pretty much built on the ashes of rome. Indeed one of the reasons why religion dominated those civlizations was because it was the church that was keeping a lot of the records from the Romans alive... and well, that's a side point.
In the last few centuries white guys managed to pull ahead, build up all kinds of massive technology, and become the dominant world power, but understand that anyone who tries to pull a "sweep of history" arguement in defense of black people is being a complete idiot. Especially with the US, while we DID keep slaves, it was basically for five bloody minutes globally speaking. When I look at what happened to the people my ancestors were from, and for how long, I am not buying any arguments of racial guilt because we got our moment. Besides which when you get technical all of the morality that did away with slavery in "modern times" came from white people, despite the passing of thousand of years it certainly didn't seem anyone else did it.
I'll also say that one thing people tend to forget is that the black slaves were not collected by white guys heading into Africa with guns and nets. The were purchused from other black guys. Traders used to load up on goods to trade in the Middle East and Africa, and use those goods to buy slaves which could be sold for more money back in Europe and America. Indeed if you know anything about slave ships (and I do from some reading) and have looked at the wreckage of ships like the pirate ship Whydah (which was originally intended for slaving before it was captured) they were set up to receive and display slaves on deck because for a number of reasons they generally didn't want to go on land in the areas where the slaves were being sold, either for fear of infection/disease, or because Muslims didn't want white men on Muslim soil. They slaves used to be made to row themselves and their owners out to the boats, where they were examined and sent down into the hold if a deal could be reached. Basically the popular fiction of the slave trade, is just that... a popular fiction. In reality most slaves were sold by their own people (ethnically speaking) in many cases being the prisoners taken in tribal wars or whatever. Plenty of books on the subject.
Once you get past all of the white guilt crap, and realize what BS there is, there is very little to really rationalize why you should have a dual standard in the media. Truthfully the actual PROBLEM is that there just aren't that many black creators of things like TV shows, comics, or anything else. To start seeing more black characters what you need is the black community to get enough people interested in writing, drawing, and similar things, so they dedicate themselves to it, and then from that creative pool a few will begin to see their work get accepted. That will lead to more movies being made with black characters, more comics with black super heroes (and movies), and more science fiction novels with black protaganists, etc...
Right now the situation is that whole "git rich or die trying" mentality, and the associated problems guys like Bill Cosby have talked about. Simply put in US black culture, blacks consider it wrong to live normally, and fall into a rut, or to try and throw themselves at an industry like comics, knowing that the odds are against them, and that even if they succeed they probably aren't going to be super rich. Rather they'd rather play the odds by doing something like basketball, or take acting lessons and hope to become a movie star, or turn to crime. It's either the very top, or the very bottom, stuff in the middle like "writer guy" just doesn't appeal, which is why it's so bloody rare and doesn't have much of an impact.
There is absolutly no excuse to change Heimdall's ethnicity, other than political correctness. The arguement that it's okay to do this, but not to "flip" a black character over to a white person because of there being so few black characters, when it's the same thing (and equally ridiculous) is simply wrong. If you want to see more black characters, then you need to encourage more people in black America to go to school, and become writers ans artists to create those characters.
To be honest in cases where we have seen characters "flipped" to white actors, there usually have been some excuses, among them of course finding someone who could actually play the role. A very differant situation from the "Heimdall" situation where there were probably a lot of white guys on the market who could have done that. Heimdall was "flipped" simply to have a black guy, there was no other reason. In the case of say "Prince Of Persia", I can't think of one Arabic actor who could have pulled it off. Heck, I can't even think of that many Arabic actors, how many people of Arabic ethnicity actually work in Hollywood? I mean sure, if you could find me a good Arabic actor who looked the part, could carry the acting, and do the Choreography as wekk as Jake could, and who applied for the role, then I'd argue there was some racism involved, but honestly I very much doubt that was the case.
When it comes to situations like the Heimdall thing, and race in general, I'll point a finger to Asia. It was a long time before those of asian ethnicity had a strong prescence in comics, but it happened because they got invested in the medium, and started producing artists and writers. They introduced those comics to other markets, and since the work was genuinely good, it began to inspire them. You then saw the eastern and western take on comics cross pollinating, and influances from both affecting both markets. Nowadays there are a decent number of asian characters even in American comics, but that is largely because of there being decent numbers of asian writers and creators.
Now, I will point out that in the course of these arguements I do tend to notice a lot of people who are black or hispanic nowadays mentionining asians as an exception to racism because their penetration into culture hasn't been unnoticed. The thing is though that they worked long and hard for that, and as there really wasn't much actual racism present, they succeeded. Back in the bad old days there were plenty of racial slurs for them too, used just as much as the "N" word or various insults towards Hispanics and Latinos. When racism subsided, they took the oppertunities, and that's where the big differance is. That black kid who blows off school to go play basketball, aiming at being the next Michael Jordan, who likes comics might just put down that ball and go pay attention in english class, and/or cultivate their drawing skill. Chances are he won't ever make it into comics, but if enough of them do this, eventually some will, and then we'll see black comic characters people will appreciate, without people needing to resort to the travesty of politically correct casting desicians. See, like most people, I don't care what color a super hero's skin happens to be, what I care about is a good character, and good storylines (and decent artwork of course). I think "Spawn" sort of demonstrated how little ethncity matters to a comic character. It's just that most creators tend to make characters of their own race (call it self projection and personal power fantasies even if they don't admit it), there ARE execeptions, especially when dealing with very prolific creators, but that's what they are, exceptions and not the rule. That's why you need more black creators to solve the problem, and for it to work they need to earn their way into those positions.
Ah well, I'm rambling, but that's my thoughts on the subject. No need to correct me on the history part, this was a long post, and I was being brief and basic intentionally. I'm well aware of there being exceptions in there to some of what I said, but this wasn't meant to be an all inclusive treatise on the subjetct since it was all leading up to my points about comic books (and heck the creative industries in general) and casting.
Like many things I find myself disagreeing with Bob, he leans pretty far away from me on the political spectrum I think, and also tends to be a little too narrow in his thinking. I think it's absurd to make a point based on racism, when racism was the way of the world in the time periods he was talking about, and what's more it had been going on for thousands of years. If you want to get technical white people didn't create racism, but we WERE the ones who pretty much ended it, at least within our territories like the USA, and this at a time when we're acting as powers with global reaches. All of this, when in reality we're probably the planet's "late bloomers" and wound up getting it more than anyone before the last few centuries. "White Guys" as we think of them (ie Saxons and such) were not really a big deal until after the Dark Ages ended, so that means we've had what? A thousand years, out of which we've been dominant for 500 or 600 or so... compared to the scope of history before that?
Like it or not, the above points are what I tend to use to make white supremecists cry.