If that was even close to the direction we had ever intended to go with BattleMaster, we would have started moving on it long ago.
Obviously it's in Tom's hands, but I feel pretty darn confident stating that BattleMaster is, and will remain, a free game, with no advertising, and no "freemium" features beyond the minor donator bonuses there have always been.
Monetize a game does not mean make it paid or filling the game with ads. There are many other ways to m8netize a free game. That would allow it to achieve a more professional lvl with plans to retain players