Xmas in April!
I am so glad that the Player's Guide will be out soon! I think that once players get their hands on it they will fall in love with Kalamar as much as dungeon masters have.
As for the D&D vs. d20 thing, speaking personally, I have encountered some pretty munchkin d20 crap, frankly. Either unbalanced or just not well thought out. By being D&D, one not only gets a stamp of approval, one gets what that means -- namely, a stronger guarantee that this stuff will NOT be unbalanced munchkin crap. Frankly, once you say you are D&D the bar is higher and I don't think I as a consumer am alone in being much more likely to buy D&D than "just" d20. That does not mean I will never buy d20 that is not also D&D, but given my limited bank account, I will be more likely to give D&D stuff the first look (and often, purchase) before turning to other d20 stuff.
So far Kalamar has impressed me as a game setting, and I do not expect to be disappointed with the Player's Guide. And this from someone who in an earlier incarnation wasn't seriously considering going beyond the original "core" 3 books!
I do not know the demographics, but I would be willing to bet that there are more people like me that will take Kalamar to be a prime purchase option, partially because it IS D&D, than there will be people that will not buy Kalamar because of some OGL worries. The Kalamar creators are taking that same bet, and I hope they win. Time will tell. So my vote is: Keep the D&D moniker!
Hack on!