Nah, you wouldn't have to draw a line from one point to itself. You'd draw a line from the Sorcerer's 'eyes' to any other part of his body or base. That'd be easy.
Anyway, I certainly see your point. The fact remains that your position isn't supported by the rules.
I agree that the way you think the rules are is, in fact, the way they ought to be. There ought to not be a line in the BGB which states that all psychic powers are shooting powers, but it's there. It'd be nice if, since it is there, each psychic power were written to account for its existance--but they aren't.
Ultimately, the question really comes down to one of degree.
If I have my Sorcerer use Warp Time and Bolt of Change in the same turn, I'm cheating. Pure and simple. In fact, I frequently do have my Sorcerer use Warp Time and Bolt of Change in the same turn. It is one of the many ways that I cheat at this game (along with failing to allow enemies to target my models in combat with shooting attacks and pretending that Ordnance weapons are capable of hurting non-vehicle models, to name a couple).
It is my opinion that Warp Time is sufficiently different from a shooting power as to warrant cheating in this way.
I do not feel the same way about Gift of Chaos. It is, basically, a shooting power. You shoot someone, and they maybe die. Sure, it is both more complicated and amusing than that--it happens in a different phase and ignores a bunch of shooting rules--but it's basically taking a shot at someone.
Think about Fury of the Ancients. It breaks all sorts of the rules for shooting attacks, but we still consider it to be a shooting attack.
Simply functioning different from other shooting attacks--even to the point of being used in a different phase--is not sufficient to make a psychic power anything other than a shooting attack, and all psychic powers are shooting attacks by default.
If you want to use Gift of Chaos twice in a turn, go for it. I cheat with my psychic powers, too. I just want you--and everyone else--to know that it is cheating. You are not playing by the rules when you use Gift of Chaos twice.
If you were to play against me, I don't think that I would be inclined to let you use Gift of Chaos twice, as I think that it ought to be considered a shooting power--and the rules absolutely back me up on that (silly though they may be.)
I find that, in fact, most people only have the vaguest grasp of the rules of this game. Often, they play the game as they learned it from someone else, or by the third edition rules, with only those 4th edition rules that they happened to pick up while skimming the book. Most peoples' understandings of the rules derive from a smorgasbord of anecdotes, speculation, and 'common sense'. Most people break the rules in countless ways without ever realizing it.
I'm not telling you not to cheat--you can play the game however you want, and there is a laundry list of nigh-universal cheats which really do improve the game. I just think that people ought to know which rules they're breaking.
edit I: You'll note that destp has corrected me about the form of the rule in the BGB. You'll also note that the distinction between "all powers count as shooting attacks" and "all powers follow the rules for shooting" is irrelavent for the purposes of this discussion.
If a power follows all the rules for shooting except where stated otherwise, it cannot be used in conjunction with another such power. The rules for shooting state that you can only shoot once per turn. Following the rules for shooting would prevent you from shooting twice--even if both times, you are shooting with psychic powers.
There is no functional difference between following all the rules for something and counting as that thing. In fact, the latter is merely short-hand for the former.
The section in the Chaos Codex isn't particularly relavent, either. It either forms its own separate set of restrictions or refers to the set of restrictions discussed in the BGB. It does not replace or alter those restrictions. Regardless of what it is, the rules in the BGB hold sway.
edit II: In response to your last edit:
There is no number of changes to the rules which can denote changes to other rules. Gift of Chaos does ignore or alter a significant portion of the rules for shooting. It does not, however, ignore any that it doesn't specifically state that it ignores. That reasoning is, simply, faulty. Let me lay it out for you:
Gift of Chaos follows all the rules for shooting unless stated otherwise.
The rules for Gift of Chaos state that it ignores X,Y, and Z (where X, Y, and Z are particular rules for shooting)
Therefor Gift of Chaos does not follow any of the rules for shooting.
Obviously, this argument is invalid. The premises do not lead to the conclusion.
It is simply not the case that because Gift of Chaos ignores rules X, Y, and Z that it also ignores every other rule for shooting. Frankly, that's irrational. By definition. It is still bound by every rule for shooting except X, Y, and Z (and whatever else it explicitly ignores). It does not explicitly ignore the rule which states that models may only shoot once per turn, and so a model cannot shoot Gift of Chaos twice in a turn.