The repair system in the previous games for weapons were cute, but I believe they were kind of pointless (especially for some weapons). Tell me how likely it would be for Brass Knuckles or Steel Knuckles to weaken? How exactly does repairing a Rebar Club work? Why would you need another Gladius to repair a Gladius? Does taking a broken crystal from one laser rifle to repair another broken crystal make sense? These questions, especially the last one on my current play-through of FO3, actually brake immersion. I didn't mind it, but it takes up more time than is necessary and makes me feel like stockpiling a bunch of damaged Chinese AKs to repair my Xuanlong AK. Too add to that, why would an AK break down super fast, aren't those things supposed to durable? Using stuff to repair weapons doesn't entirely make sense for some of the weapons. All a Gladius would need would be a Whet Stone, and it certainly shouldn't break the Whet Stone. You'd need to remold the cement on a Rebar Club and find a crystal that is actually better than the one you're fixing. It is currently too simple, but making it more complicated or accurate just adds to much complexity to make it realistic.
Now Armor Degradation actually makes a ton of sense and it much easier to define to logic behind it, thus it is likely still in the game. They show it at around the 17:47 mark in relation to light combat armor in https://www.youtube.com/watch?v=D5esyZPt5Joand at around the 16:00 mark, it's the cycle damage option. I don't know if can repair it, or if you have to replace it, but it looks like armor maintenance is still in the game. Mostly, it's removing plates in combat armor to replace the damaged plates in your own, or using fabric from other pre-war clothing to repair your own (and maybe adding dye).
When it comes down to it, weapon maintenance has been replaced with upgrading, and who knows extra gear may be useful for arming your townsfolk and building and maintaining your armed defenses. Where as it looks like armor and clothing may still need to be repaired or even replaced as it is shot up throughout your battles.