I want to add the specifics in aid of some's awesome suggestion.
1. Bringing the "Toge moment" as a mode.
When was the last time you really had to solve the problem of a single OP character and with very limited items and characters? It's what I call my Toge moment. It was fun trying to take down Toge with "specific" teams and items just tailored to take him down.
Not only is it fun to fight bosses with strict powerhouse capabilities but its even more fun doing self-challenges that most people have already done so in the boss guides. It would be fun if the engine provides the boss first, and then limits your choice of items and characters (making sure its possible to win with said characters and items).
What just needs to be done are two things:
a. Random picked boss and giving you a "limited" choice of characters and items (made sure its possible to win with said items)
b. Adding "self-challenges" as a form of achievement like Yamisebi's infamous self-challenges to specific bosses.
2. Puzzle (Problem-Solving) Scenarios
Imagine being given a specific enemy team with visible items as well as visible energy (aka they have no problem with energy) and you having the form of handicap by having not only limited choices, but also any of the following:
a. having either fewer HP
b. you are given a limited number of energy for the whole match but you choose what color of energies you need
c. having present afflictions already
d. you have limited number of turns to win the game
This is much like the boss battle mode, but much closer to the strategy present in PvPs. This mode elaborates those "1 single screw-up cost you the match" moments.
3. Conclusion: Solid Single Player mode for WoN = better advertising
If it was possible to make this idea possible, this could really be a good way to spread and sell the War of Ninja names to cellphone game apps and getting the much needed popularity it lacks. Not to mention that the single player aspect is a great way to further add more enjoyable experiences and give it its own achievements and token remwards.