To all of you who want a fee : there's nothing stopping you from donating a small percentage of your payouts back to the pool, really

In fact, if a fee is ever going to appear, I think it should be bounded : for example min(1% per block, 2 BTC a day). In this example, this is the same as taking a fee on only the first 4 blocks of a day. This would avoid the "DeepBit effect" where you can get insanely rich if the pool gets really big.