I thought you could retreat to the plane at the end of time but when you wanted to come back, you needed to return to a "checkpoint". This prevented the in/out strategy, particularly against boss. If you can warp at will and return like you never left, there is no challenge if the boss doesnt instakill you, which isn't fun.
Personally, I don't mind if there isn't some mana regen. I just wanted to know if "pure mage" was a viable build and possibly fun. And sure, we have potions which will help.
So, you warped out duri ng a battle and, after warping in, you come back to a different location (IE checkpoint)? Unless the enemies respawn (which probably won't happen because prior games never implement respawning), you only need to worry about the enemy you "flee" away from and the time you spent just going to that place.
