How should they address the disparity within the role?

[Supersnow845]

They have made WHM and SGE slightly more appealing before, with a short phase dps check that's outside of 2 minutes like p4 TOP.

You can choose to run SGE/WHM and move Phlegma/Misery into the phase if you're struggling with the check. Because outside of 2 minutes, SCH and AST dps is nothing special.

If they make more short phase dps checks where you can't rely on 2 minute alignment, that makes SGE more appealing than SCH in groups with weaker damage.

To be fair even in that situation SCH still was played 3 to 1 more times than SGE.

AST and WHM can be fixed with damage niches (because regen healing is inherently useless), but the entire game is designed around the output of the shield healer and SCH is just such a better shield healer than SGE