Copied from my post in "The Ultimate Fettigator" thread on the general Xwing forums:
My current list:
Fett with Navigator, Expert Handling, and Engine Upgrade
Captain Yorr with HLC and Vader
Mauler with Veteran Instincts
I have found both Expert Handling and Engine Upgrade to be game-savers, especially combined with Fettigator. The repositioning is essential for getting him into and out of arcs. The main drawback is not having any dice modifications, which can really be a bear.
Yorr can relieve Expert Handling stress, although I haven't personally been able to roll Fett within 2 of Yorr yet, but the possibility exists. I need more practice with that. Yorr's HLC and Vader is very, very potent, especially if Fett and MM can take some shields down first. I usually get 3 shots with the HLC off, and I never have to worry about turning him. I mean, sure, 34 points is expensive for a suicide Lambda, but man does he hit hard when he attacks.
MM is there to be a PS9 and hopefully get a few shots off before dying. You have to play him slowly and delay him a bit, or else your enemy will completely target him initially, which isn't necessarily a bad thing.
Fett usually lasts well into the endgame, which combined with repositioning, he can shine.
edit: Oh, and as far as Proton Bomb, I have found that players are just flat out getting better at anticipating when you are going to drop it, and can just avoid it altogether. Same with seismics. I mean, they do go out of their way for a turn to avoid it, but to me it's not worth possibly never using them. Or at best, only hitting one ship with them.
I get to try out this list today at the LGS (been playing on Vassal with it), so today we see if I can beat CommanderScrappy's list with it.