Skillstones are easy to get in Raid dungeon. Without using the +50 Skillpoint cheat in the bedroom, I managed to make a team with full skill sets.
I was also able to switch up characters whenever I get bored since I can reset the skillpoints (important) or change their roles whenever I want. Ex: Changing Tank Brad to DPS Brad.
All in all, the new skill tree and system is a good upgrade from before. If only Elly isn't bugged right now, I would have been able to kill Shika and Funeral in a few turns along with Mirel.
If you really want to get all their skills, farm the steel chest in Raids.