They do better then stack. They can be combined into the next higher strength. Burn 10k turn in points for the tool that never wears out. I don't sit on three and wait for the forth. Combine what I can and buy more tools. But as I stated above about not going after more now. Now I gather leather and mine, in case they ever update the BoD rewards.
The amalgamator made me hate this system even more than I did when it was proposed and implemented. Not because it didn't make the system easier to deal with (it did, albeit only VERY slightly) but because it was in essence just doubling down on the punishment to the players.
First we had to take an obviously broken system, then we have to PAY to get an item that makes it more manageable. They should have just bit the bullet and actually fixed the system itself. Even if combining was the only change they felt was required, it should have been changed directly. Like double clicking to combine uses with other things, like dye bottles.
Implicitly acting like the amalgamator was "bonus" we must earn, not something they system desperately needed to make it at least potentially usable was ridiculous.
Like someone else said this system could be salvaged by removing the armor designations, but the simple fact that they didn't understand from the get go that adding like 200+ unstackable items that were so hard to piece together that making desired alterations to just ONE suit could literally take months if not years, makes me just think they believe this is how the system should work, and it wont be changed.
Whats more troubling is that clearly more than one person thought this indefeasibly awful design was a GOOD idea. If I were the games producer someone came to me with this I would not only send them back to the drawing board I would probably strongly question their design abilities.
That's not a statement I make lightly, as I usually feel that I can defend choices the dev teams makes, even the unpopular and less than great ones, simply because game design on this scale is very difficult, they are undermanned and the game is beyond outdated, but really, there is no excuse for this system, especially seeing as during test it's flaws were quite clearly and explicitly diagrammed... and then completely ignored.
Result: an unused (yet simply fixed) system and in its current stat the grim poster child for waste of dev time.
Sorry to write a novel here, but it just really got to me how bad it was, and how emblematic it was for the kind of needlessly inelegant design we have seen before in systems like ship cannons for example or anything else that takes many steps when it should only reasonably take a few. It just builds tedium and crushes fun.