as Ferlaqua says, the problem is because the users is leaving, more mainly the F2P players, and why leaving the game? only is needed check how many resistance, experience and Gold needed for reach only 1 hero to maximum rank (in my case in server 21 is the rank red+10) and check the difficulty in the City Watch in easy, normal and hard difficulty, creep surge and invasions, more mainly the city watch and creep surge, those 2 game modes take the most used heroes in Colisseum and arena, for that the real difficulty of these 2 game modes are ridiculous with the new heroes upgrades by the most buyers players, and is too obvious that players only have to play in campaign only, how are they going to leave the game? and as the new players cant join in a guild because all the most active guilds are Top guilds, and as a new or returned player cant join in one of those guilds, is leaving the game again,
i no say as experience in disney heroes, is the reality of the game (and all the online games in general) and after see many players with 7M+ might leaving the game (and my guild for go to the most higher guilds), and therefore, the problem is not only of Perblue, the second problem of the game are the big buyers who are only looking for advanced players and kick small players or players who cannot reach the power of a buyer player (P2W),
well, after all this nobody want accept all this as P2W player, and is normal, nobody as buyer no want accept the defeat, but that made you favorite game get killed,
in others words, the Toxic players cannot accept the defeat and the reality, and only attack to the most weak players for easy wins,
and well, i say my opinion as a experienced player and after see the situation of Disney Heroes,