They will absolutely need to revisit the Werebeaver form. Its only downsides was being unable to collect any resources it generated during a rampage and inability to sustain form in tree-less areas, with a friend backing you up both these downsides are gone. Only way I can see balancing it is to remove voluntary transformations and limit the full moon transformation until next night or so. Incidentally, that would also fix the problem with seeing at night because he would only last for the full moon night + the next day/dusk at most. To prevent him getting ganked by Charlie, I would just give the free light players get upon joining when he changes back at Dusk.