Would it hurt if Polar was more powerfull than it is now - Well, probably not. If the game goes on, though, and I hope it does, there might come a point when Polar gets revisited, or some other card is made that makes polar the deck to beat. The foundation is there. The seed has been planted. It's not the worst - as in: least playable- thing I've seen over the years. A polar deck could probably take an overpay, brotherhood, benefactor or (why isn't it playable?) Tome deck on...
But seriously, I get both sides of the argument. I still agree with TRO in that Zann is simply unplayable even in a casual environment unless you do so just for flavour. The situation where he is useful is so overtly special that I don't see it coming up even in a casual environment. And that is the real problem, I think.