Why does there need to be an award for achieving level 15? Personally I'd feel a bit cheated because the only way to get to the higher levels was obsessively grinding achievements. I had 2000+ matches over many lvl 15s and my max level was 12. When MM kicked everyone's level up it was satisfying to see all the lvl 15 players that weren't 45. Levels don't matter and why does there needs to be an award for excessive grinding.
I'd be in favor of booting up the xp requirements for the top levels. With 45 being 3,000,000. That'll give you something to do Max.