I think this depends on who you think Cutch is. If he can come close to replicating last year, his numbers aren't far below Trouts and you get a really good 2B and a nice SP. I would make this trade, but I've been in the "on drugs" minority who called for trout to regress out of the top 5.
That's three really solid players for a superstar, and McCutchen has superstar potential himself. Trout is going to light it up as has been shown, but if McCutchen and Kipnis play to their numbers last year, this deal works in your favor. Shelby Miller is a nice bonus too.
I think I do this trade, that's a lot for one player, even if it is Trout. This trade has the potential to stack your team big time. You upgrade at 2B, get an almost equal outfielder, and upgrade at Pitching from Griffin at the least.