The hashrate should spread more. Slush, 50BTC, Eligius, EclipseMC, Bitminter are all good and responsible pools
Or use a real decentralized solution like P2Pool. Even if 100% would mine there, the network would be perfectly decentralized.
Really, it saddens me, that despite claiming different, most miners seem to not care about the Network and can't even live with a bit of variance.
Bitcoin is still in its infancy and miners need to take responsibility to help keep the server secure by spreading out the hashrate.