To avoid anyone arrive to 51% of the network, some have been thinking of ways to disincentivize the use of Pools, one of the most interesting ideas is a PoW system with two phases:
http://hackingdistributed.com/2014/06/18/how-to-disincentivize-large-bitcoin-mining-pools/
In short, it is the old algorithm (SHA256(SHA256(header))) and a new one (SHA256(SIG(header, privkey))) with this each block is signed with the private key of the miner, the Pool can not claim the reward for it.
This would allow a transition without having to discard millionaire investments in ASICs.