Yeah, well, I said Krosa because if what we want to do with this guy is fixing mana, I believe that Seal is a little better, although maybe not. Vines is usually not in if you have Seal, or few copies, but it's shroud abilities is awesome many times, and Invigorate, I just believe is way tooo good in our deck to ever remove it, even without Kavu, it's +5, as you said, for 0 mana. 0 mana, which is what we usually need, and that's why the new guy is also good. Running, 4 Invigorate, 4 Seal, 4 of the new card would allow us to run 15 lands perfectly well, or at least is should, the thing is, do we want to ??
The problem we would face, I think, running so low mana, and low pumpers, +2, +3, is that we would make ourselves really Berserk dependent. So you're right, I didn't really think about what I was saying, taking out Might ;)