You're taking this sort of thing too far in an effort to make 4e appear more restrictive than it actually is. Githyanki are perfectly playable by PCs. Their racial traits appear in the back of the Monster Manual. No, they don't have a full player write-up with racial feats and the like, but then again they are evil. From a content perspective, it makes perfect sense to provide races that are most likely to be used at the game table. Given that most D&D games are of the heroic (read: not evil) sort, it makes much more sense to provide plenty of non-evil races for PCs to take advantage of than evil ones.That's why 4e doesn't have playable githyanki, because they're generally evil, and evil things can only be monsters, and monsters cannot be PCs.
You're taking this sort of thing too far in an effort to make 4e appear more restrictive than it actually is. Githyanki are perfectly playable by PCs. Their racial traits appear in the back of the Monster Manual. No, they don't have a full player write-up with racial feats and the like, but then again they are evil. From a content perspective, it makes perfect sense to provide races that are most likely to be used at the game table. Given that most D&D games are of the heroic (read: not evil) sort, it makes much more sense to provide plenty of non-evil races for PCs to take advantage of than evil ones.
2) I think the heroic paradigm was pushed during the era of 2e, when there was a real desire by TSR to not be percieved as "that Satanic game" or whatever. Since then, that emphasis has faded.
In my campaigns, it is a decision left up to the players. I provide opportunities for both heroism and knavery and it is up to them to choose what they wish to engage in.
I find that assumptions one way or the other leads to anticipation of player action.
Now I'd argue that with a lot of the alignment system streamlinned, 4e is probably closer to older editions in allowing a wider base of assumed play, but from my readings, I still get the idea that players are supposed to be heroes.
What about other people?

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.