So what is the plan to retain the players that will "lose" their island?
BM need a fresh start, a little more support, a mobile version to help people to stay connected and avoid pausing when travelling (risking the loss of interest when they return)
Right now most of the player retention responsability is on the player not the game.
Now there is the chance to change this, because there is no point on deleting one or more islands if nothing is done to keep the interest of old and new players.
Everything you're talking about doing requires more people's time. Developers' time.
Right now, you know how many developers there are actively doing stuff?
Me.
And I have a real job, and a wife, and at least the rudiments of a social life.
Yes, I would
love to be able to say, "Here! Here is the brand-new mobile BattleMaster site, guaranteed to be at least 5000% better than before! Here is a brand-new island to move the people from our X deleted islands to, to get everyone interested in exploring again! Here are the 30 most-needed new features and big changes to make the game in general more fun to play, so everyone playing is more likely to stay, new or not!"
But as much as I honestly enjoy working on BattleMaster development, and do devote a lot of spare time to it, for me to do all that stuff by myself, at the current rates, would take at least a year or two.
