I would like to propose the idea of reducing the power of repair guns aimed on same target beyond a certain number, something like repair power of 4, 4, 3, 3, 2, 2, 1, 1 so with 4 adv. engi the total reps would be 14 instead of 16, with 8 it would be only be 20 instead of 32.
I find repairing buildings during a siege to be an unfun yet necessary mechanic and without major changes to the game it needs to stay. I believe this change would encourage a more active play style especially later in a match when some players choose to afk repair instead of play. Once a team is reduced to a single building often a game can stagnate with one team stuck playing defense unable to leave their own base alive and with very limited options yet this state can last upwards of 15 minutes with a low chance of anything being accomplished. Personally I find these moments as some of the lowest points in Renegade X and extremely frustrating, I believe even a small change to try and reduce or shorten these situations should be encouraged. Additionally it's worth noting that this change would also make it harder to disarm a beacon found at the last second with a mass of engis, I'm not sure if that is a good or bad thing but it's worth considering.