The way armour and weapon maintenance is handled could use some attention. The combination of reduced damage or protection based on the percentage combined with a limited number of free, instant repairs functionally gives armour half the functional durability, and even weapons start to be come noticeably weaker (though at least still functional) below 65%.

My preferred solution would be to introduce craftable repair kits and have the repair station work more like the repair bay using repair kits: for weapons/armour/tier to restore a number of durability points to the damaged item and remove the repair limit all together - including epic items. These are still based on standard weapons armour; they should be expensive to repair, but still repairable. Limited or onetime use items should be situational and powerful- the personal shields, the rockets (not the launchers), an AoE bug bomb that will kill any legacy in an x radius centred on the player ;)

Alternatively have the degradation linked to the durability points remaining rather than the percentage. It does not make sense for a durable piece of armour to provide less protection than its normal counterpart while still having more structural integrity.