TL;DR-- Heavy RNG that becomes extremely P2W after you hit platinum league (takes a few days, at most). At least 80% of all players you meet in the platinum league will have their favorite player at level 5 with all equipment, giving them roughly double your hp, a bit more starting ap, and an extra starting skill (which is huge). And the costs are ridiculous, if you do want to pay. $20 for 50000 gold (on discount)--for reference, it costs 43000 gold to level 1 character 1 level from 4 to 5.