An interview with Yoshida and his thoughts on healers in 5.0

[Ceasaria]

And yet for AST and other jobs, it's not like we have given suggestions for years capable of resolving the differents problems...
I can understand the problem with AST, but you need to understand that SCH is untouchable too because of the fairy, the crit sdlo spread, etc.
And because of that, AST noct which is poorly efficient and can't take the spot of SCH, and inevitably because of his utility will (potentially) outshine WHM and be preferable to pick over WHM.

So to sum up, WHM issues is because of AST issues which is because of SCH issues.
Resolve SCH 1st, then AST, and finally WHM.
After that, we should be able to look at the 3 and be able to balance them well.