Wow, it's tough, but I think I'd do it. I think Lester will have close to as many wins as Halladay. Halladay throws so many innings, which can give you CGs if your league counts that. However, you are winning in K's with Morrow and Lester. I think I'd pull the trigger, and drop Buchholz.
Take a look at mine please: viewtopic.php?f=26&t=428747
UTIL: Dickerson, Chris Davis
OF: Stanton, Heyward, Polanco
BN: Arenado, Chisenhall, Blackmon, Calhoun
P: Cueto, Strasburg, Cliff Lee, Wood, Latos, Kuechel, Kluber, Arrieta, Ross
RP: Kimbrel, Uehara