Okay. Now you're in a dungeon with a tank whose cooldowns only reduce damage by 3%-15% instead of 20%-100% and a healer who can only keep the tank alive by spending all their oGCDs in the first pull and they still have to spam tier II heals once those are all gone, or it's a wipe.
Hyperbole aside, these problems compound when you have multiple people "alternative syncked" and people don't know how to use their action sets effectively.