Re: Abilities Discussion
2GM is a good power for power replacers; a 6.5% chance of a special is a lot more useful when you're making attacks every 0.5 seconds than when you're doing it every 2 seconds. Accelerated Metabolism might let you use 2GM pretty much constantly, at least when not blocking.
If you don't have one, I'd strongly consider a block replacement slot. Given the character's style, retaliation (might) fits best, though in absolute terms another power might be better. A key feature of retaliation is that it's a damage boost on your next shot, so it's good to have a next shot does a single large hit. Frag Grenade and Rocket look appealing.
Killer Instinct appears to be an unslotted power. Strongly consider something for your passive slot -- lightning reflexes isn't generally considered the strongest defensive passive, but it it's based on dexterity and fits your theme. One of the Focus buffs in martial arts, assuming they work with guns (unknown, I've never used them) would also have potential and could fit your theme.