Re: Pure & simple: Do you want Whedon as X4 director?
Don't like Buffy, didn't like Serenity, Astonishing is good but has too much Kitty-Buffy going on....
So, it's a no.
If you want intimate and moody get Singer back, if you want dark but more comicbooky get Burton, if you want bright and flashy get Ratner back, if you want epic get Jackson, if you want visually stunning at a stunningly low budget get Snyder.
I like the thriller style of Bourne Identity and Casino Royale, so their directors could be good too.