Alright, I'll comment on actual suggestions you listed.
1. If all I need to do in regards to durability is pressing repair all from time to time then yes, it's pointless.
2. Yes, making repair hammers consumables is tedious. Because running to every merchant as soon as they restock in hopes they now have more repair hammers is tedious. Especially since bad rng is possible where they don't spawn any.
3. Connecting repair feature to crafting skill makes it necessary to pick that skill on somebody if I want to keep using my gear. I don't like when I have to pick something.
4. Durability related abilities might be interesting. But that'd make crafting skill even more essential. And such abilities are exactly what I meant by hard to implement.
5. A reward bonus for durability/gear upkeep. I'm the kind of player who prefers my builds to be perfect. If there's a reward I'll feel obliged to get this reward. Especially if it gives non-combat related bonuses. Which means this suggestion forces me to deal with durability.
Thus yes, every suggestion you pointed is either tedious, pointless or hard to implement.