P2pool is not only a good thing, it's a great thing, it's really what Bitcoin is all about.  I think the main reason more people don't use it is because it's not as user friendly as simply pointing your miners to kano.is, for example.  There are lots of extra steps to take, and granted many bitcoiners know more about the ins and outs of computing than the general public, a lot of what p2pool needs to get up and running is beyond the grasp of even your average bitcoiner.