As someone who spent part of last week *at* Blizzard, and talking to people in the company from members of their QA department, to the community team, to J. Allen Brack, Jeffery Kaplan, Jay Wilson, and Mike Morhaime himself, I can unequivocally and emphatically say that Activision is *not* ruining the Big Blue. Hell, I came out of Anaheim with more respect for Blizzard than I went in with - which was quite a bit.
The sheer pride they take in their reputation, the quality of their games, and the Blizzard name is really stunning, and what I saw at Blizzcon just emphasized that that pride is wholly deserved.
Blizzard still supports and patches games like StarCraft, WC3, and Diablo II - *years* after they've come out, and hasn't charged a dime to do it. The giant content patches for WoW that they've given for free (not counting subscription fees - and servers, bandwidth and customer service cost money mind you) would have been paid expansions in some other MMOs. What makes anybody think that they won't support and update SC2 and D3 for free as they've always made sure to do? It's Chicken-Little panicking.
As the guy who actually *broke* said story about WoW's paid character customization, I really do have the utmost faith that what Brack said in that press conference was not the harbinger of doom many are hollering that it is. First of all, if anyone expects it to be items that actually matter in the games, that's just silly. They won't be selling epics from the shop or anything. This will likely just be purely cosmetic in nature, and if someone wants to shell out 5$ for a special glowing cape or something, more power to them.
For an example ... say the paid customization comes in the form of something that players on the forums have been asking for for a while: different character models. The ability to make a skinny male human, or whatever. If they did this, it would require pretty significant effort to go back and re-model every single piece of equipment in the game so that it would look appropriate for the new character model. That's a lot of manpower for something not everybody would want or even care about. So it wouldn't make sense to bundle it in with an expansion, but to get a return on investment, you'd want to charge the people who WOULD care about it.
It's completely optional, largely cosmetic, and I imagine the same thing will apply for whatever they do with Battle.net as well. Maybe you get slightly better functionality. Maybe you won't get advertisements.
Really, people are freaking out over this when it's really not that big a deal.
As for SC2? Well, from what I've seen, the decision does make sense given that the other choices were A.) delaying SC2 indefinitely, or B.) cutting parts of the game that they thought would be awesome. It's not like they're making it so that you need to buy all three to play multiplayer - whatever additions/fixes come to multiplayer with the Zerg/Protoss packs will probably be patched in for free.
If the games are worth a full-game price, they'll get a full-game price. If not, they'll be priced accordingly. Didn't Rob Pardo say they were planning on doing two SC2 expansions anyway? This is just shifting their tactics a bit.
So no, Activision hasn't been ruining Blizzard. Diablo 3 was awesome, StarCraft 2 was awesome, and WotLK is an incredibly more ambitious - and successful - expansion than Burning Crusade ever was.
Edit: This still doesn't mean that we aren't incredibly overdue for Lost Vikings 3, though.