How arbitrary crafting is depends on the method that you're using to HQ your crafts. Once you graduate from rotation based crafting, you'll find that a non-rotation free form process is considerably more varied and that you really don't require any HQ intermediate materials. It's a mini-game of min/maxing on the fly and probability manipulation.

When crafting 4* final crafts from all NQ materials, I find that I can get the following:

- 100% around 70% of the time
- 91-94% round 20% of the time
- 84% or less around 10% of the time

This works out to an effective HQ yield of ~95% without even needing to HQ a single thing besides the final craft.

Most of the 91-94% results can also be turned into 100% just by HQing the level 50 3* materials giving you a few hundred starting quality, which is convenient if you're not mass producing a large batch.

If the developers introduced auto HQ crafts, there wouldn't be any benefit to learning the system properly. This isn't like in ARR where it was not only harder to free form your synth (lower base cp, no maker's mark, etc) but where this kind of method was required to reliably HQ the master book 2 tokens or 4* crafted materials. True, master recipe book 2s could be obtained through rotations but it was more or less a brute force method where you were heavily reliant on the use of reclaim, almost absolutely had to bait for good/excellent procs at the end for >30%, and had to throw tons of gil at it. Learning the system meant you could obtain the best recipes fairly easily/economically while it was RNG hell/super expensive for someone who didn't learn it.

The HW crafting balance is rotation friendly and heavily simplified but the price is that you'll have to spend more time HQing intermediate materials. Speed/efficiency is the benefit to learning the RNG system.