I totally forgot to reply to this, BUT this absolutely rocks!! I really dig the directions you're taking this ((especially bringing the system back into a more deadly orbit - health bars got kinda bloated over the game's life span XT ))
Having the rotating Techniques slot is an addition that's particularly exciting and the vibes in general seem rad!!
Re; Team Attacks - Group Synergy dumps can be a really cool way to do this while keeping to a tighter balance, or perhaps techniques with Chances? - Alternatively you could build a whole new system on top of this that's /literally/ an all out attack type vibe with each character having a difficult/unique Trigger and once one player procs theirs everyone can join in ((just spitballing here)