I never quite got how to not be shit at Batarian soldier, honestly. Turian, I'm fine with; perhaps the Striker is just an awkward weapon to use. (Although I have the same issue of not quite getting it with Krogans and various shotguns, too.)
It's definitely a CQB class. Using the Disciple (if you're lucky enough to get the unlock) is pretty much a necessity. You don't have too much reduction in cooldown, and plenty of ammo to survive a wave, plus stopping power/stagger effect. Plus, both Batarian classes give a shotgun/sniper rifle weight reduction boost if you want/need it.
Then again, I've had success with using an Avenger with both Batarian classes, as well as the Carnifex. Very flexible race (and don't let anyone tell you otherwise).
Asari adepts (vanilla) and Turian soldiers are probably my favourite classes, though; stasis with a scoped Carnifex wreaks havoc on enemies that can be frozen, whereas warp chased with a throw will play merry hell with the rest. Turian soldier's a lot more straightforward: hit 1 to activate marksman and vomit bullets from the Phaeston into enemies' faces. \o/
Yup yup, though I'm starting to favor the Batarian Sentinel to the Turian Soldier. The Batarian is an
awesome race to learn using shotguns with, regardless of class, because they're very forgiving when it comes to accuracy. Tons of HP, and the submission net ability is as effective as a Stasis attack (with greatly increased DOT at higher levels) or the "fire and forget" blade gauntlet (with aforementioned wider firing arc and longer range modifiers, and delayed explosion).
The Carnifex is a good gun too. Stasis/headshot combo is always fun, but you'll almost always be outscored by the Infiltrators/Engineers with sniper rifles.
Takes too long to Stasis the enemy and then line up a shot. Learning how to take the shots without worrying about stasis (and let's face it, if you can do that, a shotgun at point blank isn't much harder to weild), you'll be able to do
anything with just about
any race. Of course if you're not worried about scores, then by all means it's a sick weapon that will get you out of a LOT of tight spots.
As for Krogan: it's not about shotguns, it's about melee. They're the battering rams of the game. Used appropriately, they're more devastating than any other class (except for facing Banshees). Not my cup of tea, but once I get a little better with my Batarians I'll probably start mastering the Krogan. I also need to unlock two of the Krogan classes though.