I consider current PoW a complete dead end unless you can do something outrageous like enforce p2pool at the protocol level.
If I can make a coin using PoS + reputation that most people would estimate would last years, if not decades or more before the security model really had even a chance to break down, how is that worse than Bitcoin when Bitcoin can collapse at any second?
P2Pool is not a solution, because it
can be attacked with the Share Withholding Attack. I've pointed this out many times, but my point isn't known by most people so it gets forgotten.
Agreed the centralization of pools is a fundamental and yet unsolved problem.
Edit: this
Ethereum blog post discusses some of the incentives to centralize pools (see the Pools section).