we play with people who just skyrockets the difficulty score with their levels (and levels adquired by buying things...it's unfair),
Just to be fair, player's levels don't raise up the difficulty of the missions, that's just an aestethic thing. People "skyrocket" the difficulty score because they win matches, so their ratio increases. Every time you win, you add 0.5% to your personal score, when you lose it decreases by 0.75% aproximately.
The thing is the playerbase is pretty small so we can't afford to have a strict matchmaking to even the games.
I personally know what playing high difficulty levels is, and its unfair to newer players, those games require to have a good setup of characters. Ultimately that happens in all online multiplayer games, there are times you can pick the characters you like the most, but at last, we all want to win and we know that we must pick the strongest characters for every map (and yes that involves not picking 2 snipers in close range maps).