Actually you only need 1 of them. They did a huge mistake and giving you the player 5 companions.'
Everyone should have no more then 3. 1 tank 1 healer 1 dps.
Of course sadly the companions role is nothing else in swtor something that will have to die first so the players
can maybe kill that mob group without maybe dying himself.
Companions is a sad joke in swtor. The tanking companions cant tank what so ever.They can
take agroo but that about it. The healing companions are a complete joke, and at low midd lvl they have no function what so ever. Same with the "DPS" companions.Their dps is well a joke to be honest.
Sad fact is unless you are +4 to any mob in this game you will feel un heroic and like a joke
Why will you feel like a joke ? because without companions in swtor you will die do any mob group
like 2 strong mobs and 3 weak mobs in no time.Companions have 1 purpose, to be killed within a time
that you can manage to kill most of the enemies if you are lucky.You know like other games the "hero" is you.
Not in swtor, your just someone to follow a line while getting companions you need to grind gear for in the hope they actually have a good story to them.
My advice is, grind mobs you own lvl alway until the mobs are -5 your lvl then do the mission, atleast that way you will feel alittle heroic and can sometimes solo the stronger mobs groups.Now a skilled player have np taking on mobs his own lvl i'm talking about new players to the mmo genra etc and players who is not so good as some of the others more veteran players.
But as i said, everyone really only need 1 companion in this game, if they gave everyone a healer that could actually heal thats all the backup you would ever need.The only reason one would care about more companions as i said would have to be for the story aspect around them.
I'm level 47, and have used Khem as my tank since I got him. A day or two ago, I traded him in for Xalek, and last night, we finished my class story arc. Most of the way through my levelling, I have been questing at one or two levels above my level, and have not had a single problem with either of my tank companions.
Both Khem Val and Xalek make for excellent tanks (even with Xalek's shield being bugged).