What?
Of course the game should be fair. It's easy for us who have accumulated looms and levels and the hours required to develop a basic skill set to say this pile of crap, but this kind of attitude will drive away anyone who isn't heavily invested into this mod. When these heavily invested people begin leaving due to whatever reason, the population declines without anyone new to fill their place. Being "more powerful than others" should come as a result of skill, not given due to game mechanics.
With that said, XP isn't the only problem. Banner balance, as much as I love to be on the good end of it, is a team balance wrecking cancer.
They very easily could allow people of the same banner to be on the same team, and still have relatively balanced teams (in respects to player skill, i.e. K:D and score balance; as well as a semblance of class balance).
I'm guessing 90% of the time people of the same banner would still be on the same team.
Too much balance = no multiplier
Even when teams are "balanced," one team may consistently win due to player choice, strategy, class composition, and spawn differences. It'll be incredibly difficult to ensure equal balance based on teams' winning percentage. I think it should stop egregious amounts of ranged cav, melee cav, and ranged on a single team at least. Melee can generally counter each other based on equipment choice.
All games that pitch coordinated teams against randomers are unbalanced.