This is a complicated issue for me personally, and honestly I feel both sides of the debate are both right and wrong.
First, the "whiners". No, I don't think they're whining, in a general sense, but theres two types of people here, theres people talking trash about the game who haven't even played or bought it, saying its garbage or "just bad" etc, and theres people who have and complain about legitimate issues. The game SHOULD have an offline mode, bottom line. It's not that difficult, you just have "offline" characters, and "online" characters, and cannot transfer them over from one to the next. I personally feel that the game is a SHIT load better online and played in public groups or with friends and feel that the online experience is truly where the game shines the brightest, but to only restrict it to online is pretty shameful of Blizzard. Letting players experience both options and choosing after would bring MORE customers.
You know the only reason they do it is because they want every single purchase of D3 to be a potential auction house user, because overtime that's going to make an extreme amount of money, and every "user" counts. Personally, I disagree with this, and they should give us access to both online and offline, and SHOW us WHY we want to play online through example.
Second, there's the people defending Blizzard. The cheating argument isn't a valid argument if you keep offline characters from logging into the game. That way, cheaters can just cheat by themselves if they must, but don't affect ANYTHING online. Also, think about how many customers they have missed out on by only doing online and its pretty astounding actually.
However, its my opinion that if you are reading this and you're still super bitter about the online only policy of D3, then you're missing out on an incredible experience. My friend lives in Thailand and has a very sub-par connection, but we have very little problems skyping and playing together. Even to play it solo is almost tragic and a very shallow experience compared to any-sized group online. The game is AMAZING, and is AMAZING on STEROIDS when played online. The entire experience was designed around it, which can be seen as a evil thing, but the online experience is a gameplay work of art, in my opinion. That said, the lag still need's to get a bit ironed out right now but is more then playable.
Also, I feel like I should say something about the launch too. I understand it wasn't the smoothest launch ever, but I still have to side with Blizzard PARTIALLY here, because the fact they even got it running at all is a technical achievement in its own right. I mean, were talking about a launch to the biggest selling PC game of all time, and servers were up and running an hour after launch. Of course, not perfect, but you have to consider how many people were all trying to cram into at once. The next day was bad, but again, think about HOW MANY PEOPLE WERE TRYING TO GET IN, its astounding the servers didn't explode and set all of Irvine on fire. Regardless of how you feel, technical limitations can only go so far. We have to give Blizzard a partial break here, in my opinion. We waited 11 years for this game, I don't think waiting for one extra day is going to kill anybody. Still that doesn't completely excuse them from it, because the people who just wanted to play it single player, w/o lag, should have been able to.
But again, It's still my opinion that I understand why Blizzard chose to have it online only, and for the most part, I agree with them. I don't think that excuses them from any criticism, because I still think there should have been an offline mode, but really, to me, its not the end of the world, considering its an amazing game, and even MORE amazing played online, which is the only way I would ever want to play this game, and really how it was meant to be played.