I agree with OP on using Aetheryte, though I think I would prefer something along the lines of:

*Remove Anima cost for teleportation and accessible only at Aetheryte crystals/gates
*Put a recast timer on "Return" ability, longer if used when not KO'd
*Increase further risk for death (i.e. penalty) - increase return recast timer when KO'd
OR
*Return command returns player to home nation

There's a few inter-related systems to consider...I certainly don't envy the dev team's position! SP loss for a death penalty seems an unfair timesink in a game that aims to never end...and Gil loss is a timesink by extension.

The penalty can't really be something that takes too much back from a player's efforts, so I went with home nation....though any way you look at it, the player has to lose something in order to deter the desire to throw oneself at tough or multiple adversaries!

I feel the current format is a bit of a luxury we could do without.