Self-found mode is all that needs to be said.
ssf on the list (as ladder option/items merge to normal after)

It would make the leaderboards actually compelling to look at/a true competition.
You can't pickup anything that was picked up by someone else is how I would program it.
Stackable gems/runes is most what I want :D
Maybe official lootfilter do i don't have to use mods.
And ability to see min/max Rolls on affixes...
among the most popular, yep. What else do you like from the list?
There are quite a few ideas that aren't mine and deserve some appreciation