It is hard to gather in diadem...
Lots of horrible monster that can see past your invisibily...

Gathering in diadem is a challenge !
A battlefield, where you need to be better than a ninja... To collect your node.

Gatherer can be in diadem as much as DoM and DoW
They just need not to be able to loot (just like Alexander savage invisible loot if you down it a second time)
But in the same time... It would be nice for DoM and DoW to have a reduced cap of participation if a DoL is in the party

...

Does some star rank can be trigger with gathering ? Like some old S rank in ARR
That would put gatherer in a better place...
And we would see less discriminating PF against gatherer

There should be penalty for teams that do not finish their diadem's goal
Forcing them to kill a bit more low level monster or forcing themto gather or fly around for crystal/hided chest