Hello HrcAk47 and thank you for the report.
By leather jackets, do you mean the craftable ones or were you unable to repair some other leather jackets with leather sewing kit?
Regards,
Geez

Hey Geez. I meant the lootable jackets (Riders jacket, leather bomber jacket).

Right now, they are repairable by regular sewing kit, like any other top in game. But, since they are leather jackets, I believe it would be more logical if they were repairable by Leather Sewing kit.

Also, they should become more tougher and waterproof, they offer no advantage to plain hoodie.

Hello HrcAk47.
The issue with sewing kits and bomber jackets has been confirmed and scheduled for a fix. The riders jacket issue has been already fixed internally and it should be fixed on Steam soon. As for the rain protection, both of the jackets have very high water resistance, however that does not affect the time upon which the jackets will get wet but rather the amount of wetness they can receive. Both of the jackets do not go past damp status even when the character is fully submerged in water. That will not prevent the character from getting drenched if there are other less resistant pieces on the character that got exposed to the water though, as the wetness status is a sum of wetness of all items that are currently equipped on the character - the system is not definite and still will be tweaked in the future.
Regards,
Geez