If you had the power to add one feature no questions asked, what would it be?

[Payadopa]

Redo the dang loot system.

If someone's inventory is full, as soon as loot is available, toss a warning up for them so they can throw something out. Ideally, have a 'holding space' for like... 3-4 items, where if your inventory is full it goes into that space until you have discarded something, at which point, the next item in the 'holding space' falls into your inventory. (I've had friends whose inventory was full after a map night lose out on things they wanted. And I know someone who missed out on an ultimate clear totem because their inventory was full and they'd forgotten.)

The funny thing is that I believe FFXI had that feature already like 15 or so years ago.