Birkal
Pwnemon
capefeather
Scoopapa
Rediamond
FlareBlitz
DarkSlay
Birkal's Perfect Nemesis is a great idea for a concept since it's relatively easy to do, yet seems to be incredibly fun yet rewarding at the same time. We can explore every niche role of a certain Pokemon and still create something that will hopefully decentralize the metagame.
Pwnemon's Deceiver is something that seems difficult to pull off, but very rewarding if we do thanks to Team Preview. If this concept is selected, I'd imagine it'd be something like Virizion in the BW1 metagame in that it runs multiple sets with great efficiency. I'd love to see something like this selected because I have plenty of ideas in mind for it :D
Capefeather's idea is the only other one that I really like on this slate besides my top two. Capefeather's "high risk, high reward" strategy screams "glass cannon", but there are probably a million ways to engineer this Pokemon to have a significant effect on the metagame. It will probably shake up playstyles a bit, and teach us a reasonable amount about this game.
Scoopapa's concept is okay in my opinion, and it has upside in that it will let us see BW as a three-weather metagame rather than a two-weather metagame. However, other than that I don't really like it. It adds to team diversity, but it wouldn't teach us a lot as it seems to be "what if Sun/Hail was a little better". Maybe I'm being short-sighted here, but this isn't a concept I like a ton.
Rediamond's Time Capsule is a pretty quirky concept. It lets us see what the role of an old-timey Pokemon would be like in this generation, but other than that, it doesn't teach much about the current metagame. We can already see what previous-generation Pokemon do by looking at them in the DPP, RSE, GSC, or RBY generations, so it teaches us very little about BW2. Not a bad concept, but it's not one I'd like to see implemented.
FlareBlitz's concept is interesting as well. However, I don't like its premise and what it desires to accomplish. By creating a Pokemon that punishes the creation of harmful field effects and rewarding beneficial field effects, we'd just exacerbate a problem with the metagame as it is (well I see it as a problem. Others may not, but this post is my opinion so bleh!) Furthermore, since only certain field effects will benefit this Pokemon, it may make the metagame even more one-dimensional. If you like field effects having a large influence on Pokemon, then I guess this is a nice concept for you. However, I am not one of those people, so I did not vote this concept highly.
The first Utility Counter was an utter failure if you ask me, and I'd hate to see another Krilowatt (pre-revisions) made. I voted accordingly :P