The reality of the current game is that tanks and DPS can carry dead healers for most content in the game almost as well as healers have been able to for most of the game's life.
More times in EW than ever before have I been able to save a healerless group or clear a fight on my own as a tank, or as more than just PLD. The goal behind such a change as global Rez availability (which also exists in places like Bozja and sorta in Deep Dungeon, so no guarantee that it'd make its way to mainstream battle content) would be to put healers on equal footing with all the DPS and tanks that just get carried through fights learning nothing (though technically, the most common case for 8 man+ fights nowadays is to just completely skip everything valuable to the experience).
That removal of responsibility from healers wouldn't necessarily mean that their job would be even easier, because now players can be allowed to die more easily, especially to heal able damage since a group can much more often be counted on to have healers alive.
But, given their track record of removing responsibilities and putting nothing in their place that's more interesting (Enmity, positioning, pet management, MP management, TP management, melee downtime, resources that may be spent for mitigation/healing OR damage), if they did expanded rez availability I'd expect it'd go exactly as "now healers don't have to rez, also instead of being double raised I get quintuple raised".
Their track record for using new stuff as a test bed isn't great, either, given what they could have used from with Unreals when rebalancing for the stat squish and better balance new content, or could have used from Bozja to make for more interesting FATE/zone design... There's a lot of great little things in side stuff that just doesn't make its way into the normal stuff, so as much as I adore Criterion for its encounter design and relative lack of 'this attack always pick DPS or support', and as much as I love the diverse job design in PvP (and how often players make suggestions to incorporate PvP job elements into PvE jobs on these very forums), I'm not holding my breath for these changes, exciting as they could potentially be.
Edit: uhh and that relates to this thread because uhh... Meleewalker, Meleetrail they could really shake things up if they used bits of stuff from Criterion etc that might give jobs feelings of being distinct again and not just beholden to strict encounter design and predictable DPS performance