Tl;dr: My position is simply that rather than lowering the skill ceiling of the jobs and/or giving players the choices by which to strip their jobs of depth --and pretending that MCHs (with a comparatively shallow kit) don't already complain about BLM rDPS outperforming them or that build variance would surely never be subject to similar complaints-- you just stop accommodating that bull. You leave kits interesting and capable of high ceilings, repairing what cracks and mending what cuts have already been put into them.

It's absolutely fine if the floor is lowered so long as it's moved by a far greater amount than is the ceiling, but in at least a majority of new expansions, the ceiling should increase to compensate, rather than changes going in only one direction. Conal/line AoEs no longer requiring a target? Totally fine. Hypercharge using ammo instead of a duration? Totally fine. A skill notoriously slow to activate and with no use cases for its delay losing that arbitrary distinction? Fine. Awkward lockouts that even those managing well get no kick out of (e.g., Searing Light pre-change)? By all means, sure, get rid of that bit of awkwardness, especially if the change would allow surrounding skills more flexibility and therefore use cases.

But do not accommodate requests that would nearly so greatly affect the skill ceiling. Don't do it through a talent system that you'd later be obliged to balance, thus defeating the point and at most slightly delaying the issue. Don't do it through trimming the base kits. Just don't do it. Period. It's as simple as that.