I never want to play any of the other English clubs in Europe - not unless the alternatives were much harder.
There's little between Villareal and Arsenal, so I'd much prefer to play Villareal as I don't really care who we beat in a final - winning it is enough - but losing to a La Liga club isn't the double whammy that losing to a fellow English club would be.
I'd also feel a little more confident against Villareal. Nothing between the sides, really, I just think an all-English final would make it 50-50, whereas I'd make us slightly bigger favourites against Villareal.
Whichever combination of the four get to the final, I think it's going to be a very tight game that's tough to call. I'd make us slight favourites out of the four, but not by much. Bigger favourites in the two legged S/F, but the final will be very difficult to call.