It's not a good idea to wipe the whole data. Dont you think it would be unfair or bias between donators and f2p players? They all have their progress and time spent, however the compensation for the both is it fairly distributed? I dont think so. Coz the most prior player who compensate here is those donators. Isn't it? And better discuss also whats the compensstion so that it would be both fair for the parties(donators and f2p players).
And maybe f2p player would agree if their are changes to the game. Especially the hp and dmg bug. And regards to dummies account is it too much for the server having multiple account? Does the server can keep up?
I agreed to one who commented that it wil be best if wipe the data of those who not played for 4-6months and add server. That's the best solution I recommend too.