There isn't an effective gunnery commando, any elite commando dps can easily be replaced for the better, by an average vanguard. And an assault commando is a poor mans assault vanguard. I call them commandos with buyers remorse, or people who are smart enough to know they ****ed up but dumb enough to stick around on the class wasting their time.
If you've read many of my previous posts, you'll know I feel pretty much the same way about commandos/mercs in general. My point is not that they are better than other classes, but that neither DPS spec is the defacto 'PvP' spec. Nothing in 2.0 appears to be aimed at changing that (which is a good thing).
Whether we'll be improved in PvP remains to be seen.