The issue is that it seems they designed the recipe progression with the idea in mind that you'd be cross classing every skill. They could take advantage of different traits so that the classes function a little differently. Perhaps they could implement this into Standard and Advanced Touch, as in when you use these abilities you get a secondary effect that varies between crafting class. I'm not a 4* crafter, but I have yet to find a use for these skills outside of Ixali quests.
It'd be nice if they also looked at poor skill implementation. Ingenuity I/II and Careful Synthesis I/II stand out. Once you get the "II" version there really isn't any reason to use the previous iteration. Waste Not I/II probably fit here as well. I've already touched on Standard and Advanced Touch getting a rework... did you see what I did there.
It'd be nice they quit with the Flavor of the Month style crafting updates. Three Star crafting gave PbP a purpose. The most recent update gave Reclaim/Rumination. Don't get me wrong, forcing a shift in the meta is a good thing, but they aren't doing this. Hasty Touch spamming is still required to do anything end-game related for crafting. I thought it was idiotic in 2.0 that Hasty Touch and Byregot's completely trivialized 2* crafting. I still think it's idiotic that this same approach dominates.
If 3.0 brings anything it should be a way for crafters to get HQ recipes through a means other than just getting IQ as high as possible for Byregot's.
Also, they don't have to necessarily remove cross classing out right. Even DoW/DoM jobs get two classes to cross class with. It'd make a hell of a lot more sense if they had designed crafting this way as I think it's really asinine that you are required to level up all of the crafting classes to 50 solely for cross class abilities. You might argue the whole gimmick of the game is you can be all the crafters, but the current implementation is telling us that you must be all the crafting classes. Really kills the novelty if you ask me.