Champion or build up a 5*

I currently have 5 championed 4s and 8 championed 3s and a level 315 OML 3/2/2. Should I build up another 4* to champion or build up OML?

Here’s a link to my roster: http://mpq.gamependium.com/rosters/Phaentom/

Really depends on what you want to play. If you don’t mind the matchmaking algorithm (it’s changing in Mar anyway, might be better might be worst), I would max oml. That has the most impact but because of the way matchmaking algorithm currently works, you might not like the outcome. There are a few thread of players who are stuck in high level 5* battles now.