We can definitely salvage parts that are useful and can be made to fit with the 'rest of the game' though. There's a fair few things we see that some of the ultimate raiders will make comparisons to. For example, in the latest EX there's a bit where 2 people have to take tethers, and keep swapping who's taking them before the stacks they give hit 5. At the same time, 'limit cut' numbers are above people's heads, saying who's gonna get cleaved. As soon as I saw it, I said 'ah wormhole' and we tried to solve it in the same way, ie 5/6 takes the tethers first, so there's time for the debuff to fall off before their cleave. It's actually 7/8 who start with the tether here, but the point remains the same: I associated it with an ultimate mechanic, and it turned out to be very similar solution. They love to do this with other mechanics from savage too. EG: the patch after Titan and his big halfroom punches, we got Engels in the 24man and his big halfroom punches.
People say 'dynamo/chariot' for in/outs because of UCOB, people say 'rot' for literally any mechanic where a debuff is passed via contact (even if the debuff doesn't work like rot, 'it times out you die' is rot everything else isn't), people say 'limit cut' every time a 1-8 number appears above their head
And for the UWU KB, negation via shield was definitely the intended solution. At the time of release, BRD and MCH did not have Arm's Length in their kit. Nor did tanks, PLD had Tempered Will, WAR had Holmgang and IR (if it lined up), and DRK had to try and time it right with Plunge. And at the time, Plunge's animation-vs-effect difference was awful. Like, Benediction level of delay. Still remember having to use Cover as PLD to allow both myself and the BRD to avoid getting kb'd by Vacuum Wave in Exdeath (doorboss ver), had a macro for it and everything.
Reminiscing aside, yeh, we could definitely have mechanics which say 'hey have a shield on for this'. As a very quick example, let's take an example boss, who has a raidwide called, idk Blast Wave. Instead of casting it, and it does damage once, we could have this raidwide do TWO instances of damage. One with a static value of say, 200 damage, and one that is scaled to however much for the raid's difficulty. This '200 damage' raidwide could be flagged as 'unique' damage typing, or even better, introduce a new 'yellow shield' icon to say 'hey shield against this one to negate something'. Since that 200 damage is calculated 'first', the shields you apply would protect against it before the 'real damage', and it's such a low amount of damage, literally any shielding at all will protect you against it. Debuffs would be even easier. Have a raidwide that applies a debuff, with a description saying 'Does X effect. Fully negating the damage of the attack that applied this debuff will prevent it's application.'