Playing as Croatia, I start the game with the ability to revoke and hold 10 of my 11 initial counties before I hit the limit. Now if I revoke that last title, am I really worse off than leaving that to a vassal and staying 10/10 demesne? It would seem that owning it wouldn't have any effect on my vassals, as the only ones left are just mayors and bishops. The tax reduction doesn't seem to be very noticeable, either.
I'm not sure if I'll be able to keep up with building infrastructure having to deal with every county personally, but if I left it to vassals, they would be the ones reaping the rewards anyway.
Plus my personal levies are much stronger than the complete weaksauce levies that vassals raise, so what do you think?