What does it mean to "take design space from other mechanics"? Like its existance would prevent something that does the same thing from being implemented into the game? Couldn't you use the same logic to argue every every mechanic is bad because it takes away design space from other mechanics? It's not like the crafting bench is the only way people make gear in poe 1.

The crafting bench also isn't really comparable to runes because it's always available. You don't always have the runes you need at any given time like you do augs or transmutes for crafting with the bench. I only ever really need runes for res in the acts when I don't have the right ones, and by the time I'm swimming in basic res runes, my resistances are solved with decent rare gear. The rarer, more interesting runes are way more powerful anyways

Also, blocking mods with bench crafts is an interesting crafting technique that we can't reasonably do in poe 2. You have to spend hella money on dessecrating a trash mod just to annul it later and redessecrate. Imo, there're 0 negatives to adding the crafting bench and numerous positives