I just don't see how making Toribash free would benefit. It would appeal to a larger audience since they don't have to pay, but the current audience would feel rejected. Not to mention the new people would be like, "You dumbasses for buying this game" etc. People like to feel they have power over other people, so if the game would to just become free again, the people who bought the game would feel like they were demoted, and you may loose them.
I really don't know anything about the current profit the game makes, but I don't see how you would make money from the game being free even if there were a larger audience. (Unless it ends up like Gunbound, which I don't like :/)