4 pieces. Headwear, handwear, ring, and amulet. You cannot put an Alchemy enchant on footwear nor bodywear (nor shield).
Your point is still valid, but its severity is mildly overstated.
I conducted a test the other day, I made a new character, and advskilled the three crafting skills to max level. I recieved enough perks from these levels to apply all the perks I needed for "perfect crafting." I used the console to add in the crafting materials I needed. Without going into too much detail, I then crafted the best suit of daedric armour, shield, and sword that I could. I applied +heavy armour, and +one handed enchantments to as much of the gear as possible.
I had something on the order of 780 armour value, and 140 attack.
I then reloaded, went to the same character, used advskill to put Heavy Armour, Block, and One Handed to 100. I recieved enough perks to get "perfect" in these skills. I then used console to add daedric armour, sword, and a shield.
After equipping, 380 armour, 40 attack.
Obviously, even the "perfect warrior" character would apply basic weapon/gear enchants, but still, the difference here is staggering. Going pure crafting is nearly 100% superior than focusing on the skills. Not to mention the versatility (the crafter could just as easily create stealth gear, or casting gear).
The issue is that the difference here is 100% improvement. I would be fine if it was even just 50% better. 100% is simply too much.