That would not be the definition of it working, as I have mentioned previously it would be a design change for the initial drop off in player numbers based on installs to retention.I think u still dont understand that ppl shouldnt play this game up to lvl 20 and quit so we can say 'it worked'. Its a good addition ONLY if the rest is working fine.
The team are always looking into the overall balancing of the game, this year we plan to look into the XP balancing for the entire game.
We do after all have a large player base that has made it past 20.