You hit the nail on the head that DE is treating symptoms and not the disease. Your possible solutions are good but there can be issues with those too. If rep was tied to mission difficulty then people would go out of their way to credit farm instead of xp farm as they do now at Viver. Instead of LF Viver farm it would become LF T4 cap farm and LF Sechura farm. If DE wants lots of missions instead of long missions then it's not a problem at all. If it's not what they want then it changes one problem for another. Nerfs would be incoming for Volt speed to slow down capture missions for example.