The first thing that makes endgame combat in Baldur's Game look epic is Time Stop ability.
Those who don't know about the original ability or have forgotten
This concept can be easily adapted to Tome4 battle scheme as well. Imagine a high-level spell with a long cooldown that stops everything except for the caster for a few turns(3-4 should do, I think). Of course this is immensely powerful ability and it must consume almost all mana/paradox power or have a high chance of failing for paradox mage.This is the most high-level ability in Baldur's Gate. Has a very long cast time, can be easily interrupted, but if the mage manages to cast it, everything around him grays out and time stops:
Next, the mage has a few seconds to do anything he wants - walk, cast spells, buff himself, but if he fires any kind of projectile, it will only start moving once the spell is over. The spell significantly changes the tide of most battles, since there's almost no way to protect from it - everyone is affected except for the caster.
What do you guys think? Good idea? Bad idea?