Looking back at this a week later, I have a couple thoughts:
1) The mobile market is hard to ignore, so I can understand a mobile game. I think they should have had something to offer to the audience present, and that was a foolish PR move on their part. The "will this be ported to PC/Console" question could have been answered better with "we're not planning on it, but maybe we'll consider it based on feedback."
2) This will be *something* to fill the gap while other stuff is being developed and I can play it while not at home, so I wouldn't say I'm excited about it, but I may get it anyways cause it's still Diablo.
3) Bringing a Blizzard-Quality game to Mobile could be a pretty awesome thing. The initial reviews sounded positive about the way it plays, even though it's a mobile game. I don't really like mobile games, but if this is a cut above the rest, that may be good both for this game and other mobile games along the way.
4) Part of me hopes there's some skunkworks going on. As one of the fans pointed out in the initial Q&A, there seem to be features I'd like to see in a PC/Console Diablo title. Bosses with mechanics, interacting with the environment...stuff that was initially teased for Diablo 3. If they do it for Immortal, I hope they do it in D4 and even improve upon it.
5) I don't blame anyone for being angry. I'm still not really happy about it. I'm trying to find the positives with it, but man, I really get why people are mad. And reiterating on point 1, I can't believe they didn't announce *SOMETHING* that would've been properly directed at the assembled audience. The initial responses made it worse. People deserve to be mad about this one. I just hope it ends well.
Edit: 6) I also wonder if they dropped some fairly covert hints relating indirectly to D3. All of the classes in Immortal are D3 classes. They mentioned adding their favorite classes: Assassin, Witch Doctor and Druid. WD is obviously also a D3 class. There have been subtle hints about Druid being added to D3 in the future...could Assassin also be on its way to D3?
I agree with some of your statements, however I can not agree with #3, this is not their game, this is NetEasy's game that is just reskinned with the current diablo animations, they didn't even bother to create anything new for it.