Mangoose
Arcane
Yeah, companions are paramount for level 70 and under content since Mastery, Power, and Endurance are capped. Only command/presence stims matter for stims. Get your companion to influence 50 and it'll be fine for heals (and probably rape even harder). Besides that, only accuracy/alacrity/critical are not capped so those are the stats to look for in terms of mods/enhancements. (Or rather, hit the accuracy/alacrity break-points and dump everything else into crit)Attempting to go from the class stories to highest difficulty kotet will complete wreck you, no contest. The difficulty jump is yuge. Can't even remember if they allow you to play the hard mode first time around.
I played a well-geared combat medic commando and had no issues healing the hardest veteran flashpoints, I struggled with it a good bit. Especially anytime they threw me a companion I didn't have ranked up. You have to be able to CC, play defensively, interrupt, abuse line of sight, have quick reactions, etc.,
And it wasn't because I played a healer, companions are actually really powerful in SWTOR, especially if you wear gear that gives them boosts. The other way around and the healer companion would probably struggle a lot to keep you alive trying to react to all the burst damage/stuns/etc., whereas companions can get near to a real player's DPS and they aren't required to predict big incoming damage.
Definitely one of the few times a modern MMO has done difficult singleplayer content.
oh, I completely forgot, the star base assaults. On the higher difficulty those were hard as shit to solo, but I can't remember if it was bugged or not.
That being said, item rating matters. Because the gear that drops is based on your item rating. I "grinded" my item rating up to 306 by using the Spoils of War vendor to incrementally replacing my equipment with slightly higher item rating equipment. Had a lot of tech fragments so I was able to do that on one afternoon. Now, I don't have to do it again because now only 306 irating will drop if I wear said fully 306 equipment. And I can extract armoring/mods/enhancements and throw them in my legacy bank for my alts.
Sometimes Tacticals matter. For example, Deception Assassin does not have much AOE. But with "May Cause Injury," Severing Slash causes my next Discharge to hit up to 8 targets. Not sure how I could've put up dealing with content without that. Though this isn't the case for every class/discipline.
And in terms of the Star Fortresses on Heroic 2+, the most beneficial were (1) a high influence companion and (2) high influence with the NPCs you give supplies because they'll give you stat boosts at the Fortress. Even a turret if you've got Steve Blum high.