I think the situation we had during the 3.5star recipes (ironworks) was the best balance.

Materials were all non-specialist and only the final synth was locked behind specialist. I'm fine with this, but when I have to ask my friend to craft me 9 HQ ingots and oh btw can you please also craft me 5 more final synth items, it's just too much of a hassle and as a 4 star crafter myself I wouldn't want that burden placed me and so I wouldn't want to do it to someone else either.