If bitcoin 0.9.2 was to come out with the hard fork so that newer versions no longer allow centralized mining I would rather support it and have everyone forced to use P2P mining.
I think the best solution would be if we as a community decided that each mining guild should not exceed 10% of the total network rate. This way people are still ensured regular blocks and it would be much harder to get enough groups together for a 51% attack.
I am not quite sure how you would get pool owners to accept a change that would negatively affect them. At best they would just subdivide their pools into smaller pools and carry on, possibly obscuring their ownership.