Perhaps this has already been suggested, I'm not sure.
I used to play Super mech before the big update, when mechs could be different levels via equipping parts that are equal to or below said level, and I see that many people disliked how this update took away that feature. What I'm suggesting is that ladder battles can be fought in "tier's", which could bring back the multi level mechs. Perhaps this can be achieved by having a separate battle button that can pair mechs up with mechs of the same level range. The ladder ranking would have to be separate from other level ranges. The part I'm not so sure about is that when you reach level 15 you get parts from level 15-30... this may make gathering parts a bit difficult.
I don't know, I'm just throwing this out there.