There was a huge difference in ARR end game crafting compared to HW.
The skill element in ARR crafts had to do with your management and handling of RNG. The fundamental flaw of a rotation is that it treats procs as bonuses, whereas they are not. Crafts are tuned and designed for you to utilize procs and manipulate the probabilities through free hand work. Designers know full well how many procs you will see on average, so crafts have been balanced so that on an average optimized free-hand run, you will get 100% (for normal crafts). With a rotation, your average result is not going to be 100% because you aren't efficiently using your CP (PT swaps aren't bad but BT swaps are a mega waste of CP) so if a craft was tuned to be harder like the master 2 tokens (where an average free hand run did not give you 100% even when you fully optimized your strategy) or even the ARR 4* crafted materials where below average runs penalized you with low HQ success rates, it was a major fail.
This created a huge division in crafter proficiency because the masses (to this day) just follow rotations, hence the changes in HW.
Every time you get a proc, you should be asking yourself what you can do with it. Use PT? Or maybe if you used tricks, you would have enough incremental CP to add three extra touches.
Adding three touches, for example, improves your expected IQ by 2.4 and is therefore more powerful than 2X PT or in the case of ARR, several (12) shots of BT. So why save up a ton of CP and wait for good procs that might not appear? Failure to use PT multiple times will result in wasteful BT swaps.
The take home point is that these procs are not bonuses so they can't be treated as such like how a rotation operates. Rotations work fine HW and beyond because crafts are simply tuned to be universally easy.
Once you've mastered the crafting and RNG systems, you should always be considering the following when crafting free hand:
- incremental CP costs of additional durability restores and other abilities
- Expected IQ stack changes due to your on the fly modifications to your synth (as a side note: replacing 2x cs2 with 1x rs is as powerful as 3x BT/HT swaps at a cost of 2 stacks of SH2; very powerful). I've already mentioned the effectiveness of durability restores vs waiting for PT opportunities. You should be using both.
- Expected number of misses that you will see on an average craft plus the spread. You have to make sure that your strategy is robust enough to absorb even an above average number of misses.
These are just a few points off the top of my head. There are tons of ways of optimizing on the fly.
You're dealing with binomial probabilities so these are predictable and can easily be incorporated into your design. It isn't about looking at your base starting CP and then coming up with the most efficient and powerful sequence of abilities. That's a beginner's approach because you're ignoring RNG mechanics (like ignoring battle mechanics in raids that players love complaining above). It's akin to coming up with a universal "battle strategy" on a striking dummy.