I really don't even see the need to make it a competition between the games. WoT scratches an itch. It isn't a tank simulator. WoWP will scratch an itch for some, whereas some people will probably be disgusted by it. Given what I know about WoT, I can't even imagine how well it will translate into airplanes. What I do know, is that a rock/paper/scissors airplane game won't satisfy those looking for a more realistic WWII flight sim. Given the xenophobia that surrounds WoT these days, nationalistic fervor will hit a fevered pitch when it comes time to set P-51 vs. La-7 vs. Spitfire vs. FW-190. So really, AH2 will maintain its position as the preeminent WWII flight sim. Those people looking for a more arcade-ish flying game that uses historical WWII aircraft may find WoWP more to their liking, but I figure those people don't really play AH2 anyway. Especially when the game has to "balance" the dominant uber performing aircraft with their peers, since its a rock/paper/scissors type of game, versus the hard data modelling of aircraft in AH2. HTC doesn't have to worry about how well the P-51 performs compared to other aircraft since it strives to make them perform as life-like as possible anyway. WoWP, on the other hand, may nerf or buff various aircraft away from their historical performance in order to achieve game balance.
So again, I don't really see a situation where you have to say one game is better than the other. Its seems more like apples and oranges to me. That being said, sure, the two games may compete for the $15/month of a player, but not because one is better than the other--but because the player is looking for a different type of game. I can see WoWP being a fun game, but it will never approach the realism found in AH2 by design. Different strokes for different folks.