And yet all of the reasons you stated apply to what we have now for the most part.
Difficult decision? "Well, I need more damage. Do I get Mageslayer now or save for Ashkandor?"
You can sell your early items for a benefit later on. My argument against recipes isn't that it will be too hard to figure out, although I think it's a good one, it's that it adds complexity for little to no benefit.
It seems like you can get all the benefit of items and progression without upgrades, while upgrades only adds complexity.