I find in ground combat its best to just watch my NPC's take out big groups of enemies. As soon as I start using specials ALL the enemies attack me. That poor tactical officer is trying to draw fire, but they all ignore him and pawn ME!
But If I just kill one of the easy enemies and just watch my team take out the rest, the enemies spead out on my 4 npcs and they are able to tank. However when I fire off a shot or 2 they all change aggro to me! And I can't tank 10 Klingons.
counter this by getting your stupid AI teammates to res you. You can give orders when you're dead, so make one of them stand right on top of your body and mash the "call for help" button. They will eventually decide to res you in combat.
I do not experience this, perhaps you are doing something you shouldn't? Such as unleashing a wide-beam weapon at the whole group of foes seconds into combat, or using something similarly attention-grabbing?
Also /bugged it. Happens most often with Klingons and Jem Hadar for me. I have two tac officers with maxed Draw Fire II and all it takes is one (even minor) debuff from me or AOE expose attack and I'm toast Not major, but ground aggro mechanics still seem borked.
The threat system in this game is messed up. I can have all my team members attack one klingon until he gets down to 25% health, and if I attack him just ONCE with a normal attack he'll aggro on me. It's hard to play a support character when the system is like this.