Quote Originally Posted by SleepyBee View Post
if there's even an optimal-ish build for the ast weapon at all.
There is, it's full Acc/PIE (same for WHM), but that's only if you raid Savage or do Extreme trials.

Quote Originally Posted by Miyha View Post
For piety, AST has the best MP management in the game at this point, so this is useless.
If you DPS in Extreme or Savage content like you should as a good healer, you will need the extra PIE, otherwise it's pretty useless, yes. Also, SCH MP management is still leagues ahead of both AST and WHM, and AST isn't actually that far ahead of WHM (even if you get the extra tick from LA consistently by aligning it shortly before server ticks happen), not enough for it to matter, anyway.

Accuracy, unless you're melding it and it is required by your raid group, is also pretty iffy.
Accuracy has by far the best stat returns per point (until cap) than any other substat in the game, and that is generally true for every job. There is absolutely no reason not to put it on your relic and meld it if you do Savage or Extreme content, especially since all the other substats are very meh in terms of return per point. Also, putting Accuracy on your relic allows you to meet hit caps without using pentamelded 220s while still melding your right side with Vitality V (which is still important in A8s and absurdly increases your survivability on all other floors).

(You will also likely be the main healer alongside a SCH in most serious raid scenarios anyhow.)
Being the main healer is no excuse not to DPS. I solo heal large parts of most fights as WHM and still push DPS as much as possible. A good healer duo can easily put out almost as much damage as a fifth DPS player would add, which is huge.