Yeah, FFZ values character life so much it's almost done away with the possibility of random permanant character demise. You gain so much with "immortal" characters, as mentioned above: more heroics, better characterization, better stories...
You do loose verisimilitude, on some level. In other words, you need to take the fact that people don't die very often into consideration when designing the world. In FFZ, this is dealt with in the category of necromancy, which is suitably high level: it can disrupt, distort, and destroy people's souls, prohibiting them from coming back to the waking world. There are spells to counter-act them, but it is all significantly high-level, epic stuff.
Raising a dead companion should be a legendary quest, accomplished only once in any character's lifetime. Also, it should only be available by using major artifacts or by dealing with greater powers. I actually feel the same way about wish, miracle and many similar spells.
I would say that the availability of resurrection magic should rise with the likelihood of death. Kind of like the power of healing magic rises along with the damage monsters can do, and the power of destructive magic rises along with their hit points.
In other words, if characters can only rarely die, if it only happens when facing truly vile villains at the cusp of dramatic quests, then, yes, raising magic should be rare and special, just like death. But if characters can drop dead with a few failed saves, then it shouldn't take more than a few won saves to bring 'em back.
From a story perspective, this puts equal drama on life and death. From a game perspective, this keeps things "fair" -- you're only ever in as much danger as you can recover from, if you're skilled and lucky.
While entirely realistic to play in a world where death is common and raising is rare, for me and for every person I've played with, it's not that much fun. It's also entirely realistic to play a party of commoners, but that's not much fun, either.