And all of that is not even mentioning the recast time of Ethers. Which start at 2 minutes and 30 seconds base, and skyrocket up to 5 minutes at the Super-Ether.

Fortunately, Ethers are fairly consistent with MP tables for non-healer roles until you reach Super-Ether; where it starts to fall behind. Realistically, base 2 and a half minute recast is semi-reasonable as it would fit into rotations fairly easily.

However, gaining 2,300 MP back every 5 minutes is where it plummets in usefulness. The main time you would see people needing Ethers at max level is when there are a few deaths; and the amount you get from it isn't even enough to cast another Raise.