BugManiacBob
It seems quite clear that Korski's concept (Sketch Artist) is going to be the CAP 2 concept, but I figured I'd throw this in there. Unfortunately, I don't really agree that the Sketch idea is all that great. Adding any move to a pokemon seems really cool, but in reality, it would have to have amazing stats to see it run all of the most interesting sets. Besides that, it would have to have a shallow movepool in the first place to see some moves that are rarely used for coverage, because otherwise they're usually overshadowed. I'm just concerned that we will learn very little from this CAP. It would be just another poke who could do a lot but only exists in the metagame to do 1 or 2 things.
BugManiacBob and FireBlast both had interesting psychological ideas, and that really intrigues me. More than anything, I'd like to see how messing with an opponent's prediction or mindset can alter the game. Indeed, it might not change it noticeably, but that's the point of trying! I'm a bigger fan of Psychological Warfare, because it involves actively messing with the opponent's state of mind, instead of passively doing so like Theoretical Threat. I feel like Psych Warfrare gives us a more ample opportunity to learn from this than Theoretical Threat.
When it comes to Let It Snow, Let It Snow, Let It Snow! I find myself wondering why we're truly interested in this concept. Weather is plentiful, and creating 1 pokemon to make the most underused weather viable doesn't really seem like something we can learn from.
Overall, I feel like CAP exists so we can experiment with the effects of pokemon on the metagame. I think the most important CAPs are those that are likely to affect it in new and interesting ways. Sure, it's great when we make one that's good or useful, but the point is to make one that finds its niche and truly changes the game. I don't feel like Let It Snow! would do that at all, Sketch Artist wouldn't really make anything all that new, and Theoretical Threat is a little too passive for me. Thus I go with Psychological Warfare.