kicking slimes for hours.... you may have discovered a way for square to do a weight loss RPG.
EDIT: hmmmm... the more i think about it the more it seems like this could work. small fights before the boss as your warm up, long boss fights for the main work out. a 40+ hour RPG would last months! And if you made a branching story line that had a huge impact on various outcomes and story elements, people would keep doing the workouts to progress through the different story arcs. RPG gamers would be the fittest people around. Though I would would use a new IP for the initial release, other wise they could produce a final fantasy that receives worse feedback then FF13.