I have to agree. That's pretty much the case in any class-based RPG, though. If it can wear heavier armor and doesn't care to murder anything it's not directly pointed at, it is always the combat pragmatist's first choice.
But, as far as ME3 goes - if you're importing a level 30 (or any other level that has 21 free points) then upgrade Adrenaline Rush to tier 6 and watch your enemies weep.
If the Soldier is a bit too generic for you, then Infiltrators are basically squishier long range specialists, Vanguards are squishier close range specialists. Sentinels tend to need to be up in the enemies' faces, but Tech Armor slowing power use makes them even easier targets than Inf/Van, IMO. Adept is pretty good, but as always, is meant to do very specific things for the party in terms of their role, so that makes it harder to consistently use squaddies you just like to have around over the ones that might be a bit more useful but not totally necessary.
Engineer is a pretty good choice as well, if you don't mind playing second fiddle. The upgrades for the Sentry Turret/Combat Drone practically make them into squad members you can deploy anywhere to the battlefield. Both get stuns too, so if you want to set one of them up (build-wise, that is) to dish out tons of damage and the other to make sure nobody closes the distance, it's viable - and awesome.
[Edited by Shotgunmaniac, 3/8/2012 3:02:51 PM]
by biotic I assume you mean Adept?
I think the Soldier is a bit too generic for me.. If I run out of ammo, then what do I do? Soldiers don't get any biotics do they?
Just the different ammo types, but that requires thermal clips..