The gun is being jumped pretty severly on this whole 3v3 thing. I don't think there's much motivation from VGC's end of things to change the format more than they need to - 3v3 would be a completely different game than the 2v2 they've done basically for two gens now(JAA, etc. in Gen3). I'd be surprised if they adopt it, especially considering how much tinkering was done in 2s between Gen3 and Gen4 to balance things out a bit better - it's a much, much better game now than it was four years ago and I think 3s will similarly require time to age. The old spread move mechanics, as well as how Pokemon fainting worked then were both pretty significant changes to improve the game.
Regardless, though, there isn't much value in theorizing. We only mostly even have the battle mode confirmed - can't really theorize anything until we know at least the basics of mechanics. There's no reason to assume spread moves will work the same way they do in 3v3 as they do in 2v2, for instance, which would drastically change the game. We also don't know how many Pokemon we'll be allowed to carry (3? 4? 6?), and much like theorizing in 2v2 when all we had to play off of was 1v1 produced very little, I can't imagine projecting 2v2 on 3v3 is going to get us much.
That isn't even to mention new moves and Pokemon - not much point in 3v3 DPP when it's going to be "an old gen" in a matter of months. Imagine this year's VGC without Dialga, Palkia, Giratina, and Toxicroak. Not to mention without Sucker Punch, Draco Meteor, and Trick Room...
It's fine to be excited, but even if 3v3 VGC happens there's not much good in discussing it now, I think.