Remove Rescue from the game.

[Post]

Having Rescue provide a nigh-invulnerability shield would not be comparable to its current effect in terms of what it can and cannot save players from.

Rescue is capable of saving players from things that are unhealable and unmitigable, like being knocked off a cliff, into a death wall or having the floor removed. To replace it would have to meet those sorts of functions and I cannot imagine any systems that currently exist in game that could be easily implemented to meet those functions. A "float" status to let players hover over pits would be something (though as they stand they only ignore very specific mechanics where used), or even a shield that prevents e.g. the next instance of AVOIDABLE damage (so as to prevent there being yet another oGCD mitigation a healer is expected to push instead of spamming more Glare, again damage sources would need to be categorized as "avoidable" in some fashion for this to work), but these things all strike me as spells that would need to be separate to meet the function of Rescue (which is a balance consideration when it's already got a lengthy CD) and then could also abuse many more boss mechanics themselves, as evidenced by the fact that both effects I just suggested are things that appear as additional actions in Field Operations content and nowhere else because they're so powerful.

Rescue is also capable for the utility of increasing a party's mobility options, even despite the fact that most jobs have some form of repositioning tool nowadays. A huge use for it is to save players stuck in Limit Break movement-lock, or even Healer LB3 rez movement-lock; LBs cannot always be delayed for a 'proper time' if they want to see use at all and that can force players into places where using it and dying is preferable to not using it. Rescue is perfect to pay them back and save them. Others have already mentioned how it was used in previous encounters for uptime; I can recall off the top of my head using it early pull in e4s on my co-healer (or vice versa) on Evil Earth to save Sprint get more damage in on a mechanic that slide-casting was not sufficient for.