With regard to growing Asicminer's total hash rate to more than the current 20s%...
An attacker who controls 30% of the network has a 20% chance of solving 6 blocks in a row...so even though we are not the dreaded 51% attacker, the network would still be exposed to some risk by friedcat having 30%.
Moreover - if friedcat does get 30%, imagine that competitor pools of total size 40% gets taken out (eg ddos). Now Asicminer's 30% suddenly becomes 50% of the total, and again we are the attacker.