Idea 1: a vote kick in battle. But the vote kick would only work if everyone else wants the person to be voted off. (ex. 4 people, 3 people would have to vote), (3 people, 2 people would vote, etc)
Idea 2: Storyline: The Titans from the origin of the spiral are awakening which would be a threat, And hearing the past of the spiral explained better then it is now would be amazing. We could experience actual awakenings and epic quests. In the end there would be 3 dungeons that each show the awakening of the titans, (Giant, Dragon, Triton)
Idea 3: Ancient Magic: Magic that can summon things from the past, it could be a summoning element, but here's an idea that could work also
Undo: Undoes anything you did in the 2 rounds, and restores the pips you've used by then (if you damaged the enemy, it heals the enemy whatever damage you did and restores the pips back to you)
Idea 4: The Forgery: You can turn in spells, and depending on your level, you'll get a better version. EXAMPLE: Trade in a 4 pip "Power Link" spell, and recieve a 6 pip "Super Link" at level 80.
If this sounds confusing, i'm sorry, I tried to explain this the best I could.
Vote kicks would just lead to everyone being kicked out for being "too low-leveled" or "not the right school" without giving the player a chance. It's too easy to abuse and is probably why this feature has never been seen. Personally I hope it is never seen.
Redoing would also lead to trolling. Remember everyone triggering the cheat heals of that boss in Stormriven just because they could? I absolutely do not want some obnoxious kid dragging out a boss fight by constantly rolling back to moves he's played. Just plan your moves carefully and you won't need to undo stuff.