This is a suggestion I recommended back in 2019 although Rory now seems more open to outside suggestions so here we go again
My recommended change: The bosses Kumorui & Manda are almost entirely forgotten about in the current state of nin, what I suggest is removing the current level requirements and replacing them with a group level requirement, ie the total level of all players in a team rather than each players individual levels.
Starting with
Kumorui at Group Level 110 (4 level 27's or below / 3 lvl 36's / 2 lvl 55's / 1 lvl 56 or above)
Manda Group Level 150 (4 lvl 37's, 3 lvl 50's, 2 lvl 51 or above)
This would cause almost no change to the level ranges that the bosses are currently designed for while also allowing those above the level requirements to be able to do the bosses, group levels can then be adjusted based on player feedback.
Pros:
* Revitalise old content for players
* Test a new mechanic (group levels) that can be used in future content
* More incentive to enter danger zones where these bosses are located
Cons:
* Could cause influx of drops from these bosses, although the only worth while item from these bosses is shirokata which already had an influx from land of iron.
* Could make this content areas to be taken by higher level players thus unable to be completed by the levels these bosses are designed for although these bosses are almost done by no one (especially new players who normally pass these boss levels before even knowing they exist) and this could be fixed by instanced boss rooms.