Just adding my experience to to the convo:
I have been on the Republic side and we steamrolled the Imps. Other times they just destroyed us.
Most of the time, the number of high levels on a side determined the outcome.
In one HuttBall match, the opposing team was 40's and 50's against teens and 20's. An unlucky match up for us, for sure. But, they just stood at our goal and killed anyone that came out of the starting box, for the whole game.
That's certainly not what the game was intended to be.
Some say the Bolster mechanic evens it out - nope. Close, but needs a little more work. It doesn't quite make up for gear, additional abilities, etc.
Some tell me - learn to play. I know how to play, but you can't beat a player of equal skill on a 50 when you are 20. Just not going to happen.
So they say, don't play until you are 50. What ?!! Warzones shouldn't just be for level 50's, there would only be a few games queued a day at that rate. And I didn't buy the game to sit on the sidelines until I'm 50.
I don't think it's a Republic vs Empire problem.
I don't think any class is too OP.
But without a better bolster mechanic, random chance of queuing can unbalance games to the extreme.