I definitely haven't been dreaming of it, but it would be a lot of fun as long as the playability lasted. It would definitely be PvP heavy, and I bet they'd have to do some actual balancing of something, but other than that it could be a lot of fun.
What I'd LOVE to see done is a sort of Gym Master setup where you can defeat a gym master and then become that master - then you could be challenged yourself by other players or something along those lines, and perhaps be forced to defend your title every so often.
However, I'd also like to see some group stuff, which Pokemon never really had. It would be hard to fit that into the world given how solitary a lot of it is, but it would still be neat.