One more in favour of the fins here. I just think teams need to integrate them better with the engine covers - the liveries need a redesign with them in mind. See how awful the Renault R28's livery expands into the sharkfin as an example of bad integration - it looks awfully tacked-on. The logos on the Toyota also seem to do that - just barely stretching onto the fin, leaving it mostly bare.
Also, god dammit those slicks look better used. I found the shiny glitzing examples on the launch cars terrible - but with this matte "finish" after a lap, they look so much better.