If you are only there to earn EXP and maybe tomes, there are other ways of doing that.
Im currently at i336 and this mission is what give me the most resource right now to get my i360/390 ( it give even more than alliance raid lvl 50 ). But of course it's not the best time effective mission cause it take like 30 min ( the ultima mission one )

One solution could be to remove the reward and increase other roulette reward to compensate so we don't have to farm it again but the drawback will be that new player will have hard time finding a group ... but to fix this we can add some bots allies to the player group for exemple like if it was a coop single-player mission.