Ye, the ability to band wagon is certainly part of the problem. Frankly, perfect balance is impossible for any game with diversity, even the most popular games, LoL, WoW etc,require constant balance patches. So it's not exactly fair to expect perfect balance. That said, considering how infrequent this game receive such updates, it is inevitable that there would be balance problems and it will be abused. As it were, if there are constant and frequent adjustments, then people won't bandwagon, as it costs quite a bit of resource to switch ninja in this game, mainly in mood scroll and awakening material costs, and in case of some ninja, a cost to getting them. But alas, slow update means bandwagon, so class switching for the optimal team is the norm.

If only there was some kind of loyalty bonus for not changing class....