I was a gunnery commando before 1.2 and abandoned it soon after. Now back with an Assault commando I'm actually really enjoying it.
The AP>Sticky grenade>Hib combo isn't the most damaging burst in the game but it leaves a mark. The fact that I can do it at 30m while on the run is awesome. The marauder you just pissed off will probably leap to you then (if you didn't Los him or run beyond 30m). Stock stike him, pop your defensive cooldowns and run while shooting, if you're lucky you can survive a few seconds till you can cryo him and knock him back out of range again. Follow up with your full auto, t
he Hib proc and the assault plastique if it's ready and you may 1 on 1 kill the commando killer.
I think the assault path is the key, people keep saying we're turrets but we're not, we can play in the sniper domain but focus on dots and AoE attacks rather than hard hitting 1on1 attacks.
Gunnery is dead and has been since 1.2, abandon it and the commando becomes a viable player again.
problem is if you want to play assault, vanguard is simply miles ahead, there isnt any way around this