Yeah with the skill tree , it's not as crazy as it looks. I might mod it at some point to only show the available skills you can learn "right now" and not the skills further down the progression.
It is set up so that you can learn pretty much anything you want for any of the characters (also any of the characters can equip the same items too, so you can build them how you like, although classes have their own unique trees and different base stats as well). There's a lot of ways to be successful with this in-game, the only way the player will get into trouble is if they have all 7 of their characters learn the exact same skills as each other. (As certain skills are better or worse depending on the enemies you're fighting).
But maybe a little bit more hand holding for the player on that part so they don't get overwhelmed would be a good thing to do for future titles. There's more Star Shift coming!