I am going to get crap for this, but must be said.

We have fights such as Leviathan, Bismarch, Ravana, ... Titan, Neverreap, etc
All these fights have edges were you can fall.

Yes I have fallen a few times, but the mechanic of falling off and staying dead the whole fight is not fun. You should be able to rejoin the fight via small mini game like alexander if you get sucked to the other field in burden of the father.