Gotta disagree with the OP's idea to remove those pillars, Volcano map, for all its trolling with the bomb placement is actually one of the few maps that feels otherwise balanced, for both ranged and melee players. If the enemy hides, your team needs to adjust its posture, either to bait them or to flank them at once, in a vacuum a simple concept; in practice, uh... dice roll?
Plenty of teams unfortunately get into the mentality of "huddle behind the pillar" or "don't look behind you for flankers, I'm sure the caster will be fine!" For all but the longest casting moves it's actually fairly reactive a map and allows a lot of tactical play and has none of the delay of Clockwork in regards to the doors registering a person trying to go through them.
Overall I feel it plays it safe with plenty of options for all types of players to exploit, unlike Cloud Nine which is clearly lopsided to open engagement in a mode with near oppressive levels of crowd control. It's really on teams to look out for one another at all times because as soon as one person gets focused, they likely can't escape without significant backup, ninja and dancer players love exploiting this especially.
That's actually a pet gripe I have with Guard, even when compared to its fellow classmate Purify which likewise has an issue of "animation over action," of all the abilities added with 6.1, it seems to be the one most consistent with being inconsistent, if most every other move it is there to counter is snapshot, why is it not? Heck, you can't even defend against a MCH LB before the crosshairs even show up in some cases, it's just boom, instant full damage regardless. Maybe it's easier on people who have near perfect ping, but this is an MMO, such a state of being is as rare as snow on the sun.
I know FF14 PvP will likely never reach the heights of games actually designed around it in the near future, but man, if they're pushing this direction of snapshot moves they really gotta up their game. It's not like an FPS where your actual skill at dodging, parrying and situational awareness will be the primary factors to your survival (though the last point is still relevant thankfully), the design is much simpler and prone to costly delay alas, so it's small wonder it ends up being such an aggravation after this much time dealing with it.