Who and a what huh? Hill giants are just like stone giants? When did that happen? Why was I not informed?
Okay, maybe they play similarly in combat. I wouldn't know, having never had a party of the right level to express my thwarted interest in giants. But how does that translate to "too similar?" They may have the same intelligence, but they don't act the same. Maybe they could use a little mechanical differentiation, as the kids say these days, but I can tell 'em apart.
And I'm all for limited campaigns, and the presented material does look kinda cool, but I'm not so sure I want my game system structuring my campaigns for me. On the other hand, giving characters a concrete way to provide feedback to the DM sounds kind of nifty. "Ah, Dave has taken 'destroyer of zwirfs' as his epic destiny. He must want to fight zwirfs." On yet another hand, shouldn't the DM be able to figure that kind of thing out?
I'm still looking forward to 4e. I've liked all the preview material so far. (Except for the sword wing. No hints of history, and it does nothing horrible to the PCs, fulfilling neither of my main monster criteria.) And, if it plays fun, fast, and with less work, that'll be worth any weirdness in the setting fluff. And any weirdness generally.
But those bits of it strike me as just a little bit off.