Vanek isn't even a top-20 forward, 2 week hot streak won't mean much until we can see proven production through a full season. But IdealisticSniper is taking homerism to a new level right now.
That being said Vanek is easily the best player in this deal, but he has absolutely no fit in the Tampa system, our top-6 all have great chemistry with each other and there's no point messing that up right now. Lecavalier is a hard player to gel with and Vanek doesn't seem to have the playstyle that meshes with him either, and having 2 pure snipers on the first line is just not a good idea.
Ryan Miller is the only piece from Buffalo that would be a serious proven upgrade, but at the risk of losing our future star winger and #1 D-man is just not worth it right now. Cory Conacher will be irreplaceable to the lightning in a couple years, bet on it.
Vanek is one of the best natural goal scorers in the game. Do you realize that he's 7th among all players in goals since the 05/06 season?