However if the economic incentive exists (people wanting to get the last marginal scrap of interest without having to keep their program up to date all the time) then I think it can be assumed PoS pools will develop in some form or other.
In todays PPC version you would have to trust a PoS pool with all you coins. This might not be a big barrier when crypto reaches wide adoption and trustworthy companies are established. Still I don't see why PPC protocol should ease pooling.
In today's PPC you put your own coins at risk to generate stake on your own machine (private keys are unlocked on an online machine for significant stretches of time). Sunny's proposal in this thread is about allow stake minting without taking that risk by using separate high and low risk keys. Once low risk keys exist it isn't much of a stretch to see handing them off to a trusted third party to manage on one's behalf. Were you watching bitcoin when the recent fork (and successful double spend happened?). It was 3am here but if I had been mining through a pool my machine would have been directed at the correct chain within 11 blocks of the fork. This may or may not have happened if I were asleep and mining solo. There are advantages to "professional" pool ops provided we can figure out how to avoid the security downsides.