Team balance wouldn't be so important if winning rounds wasn't so important, which basically means that current exp system needs adjustments. I think that if basic multi was x3 and after winning it was x6 until you lose it, if your team is winning or not wouldn't be this important anymore. You could level up and
progress (progression in RPGs and other games is very important feature) but you wouldn't need to carry this combo of winning streak. On the other hand the team that would have x6 (previous winners) would level up quite fast but let's be honest, leveling in crpg is slow anyway, especially when you are playing with a low-gen alt.
I don't mind people having high levels, especially when it's accessible to anyone, same with looms.
Obviously upkeep would need an adjustment as new exp-system (it could have other new features for sure!) would mess with average gold-gains. Currently upkeep isn't balanced anyway so nothing new here. Ex. Heavy Lance is too expensive (just crap wpn) and longsword + HBS wouldn't suffer from the price increment. Also 1h weapons like Arabian cav sword are 2 cheap when compared to top expensive 1h swords. Upkeep needs to be rebalanced anyway.
Just what I think.