Crafting is the LEAST RNG part of FFXIV. If you're encountering RNG in crafting, you're doing it wrong.

Even if you build a rotation with RNG (which should ONLY be Hasty Touch) you can skew it heavily in your favor by doing like 11-12 and only needing 8 to succeed for HQ.

Desynth/Melding is a different matter - pure RNG and it sucks.