Continent Filter
I'm in North America. If I join a group where the leader is from Australia (OCE groups), I will experience 200-300ms ping which I do not find enjoyable. Because I don't want to play with lag, I don't join OCE groups.

If an Australian joins my group, they will experience the same lag.

It would be nice to have a filter that would block a certain continent. I could block OCE, and Australians could block North America. This could be determined based on server name.

IO Filter
In the advanced expression query, the ability to say something like "io > 2000".
The RaiderIO addon has functions to provide this information.

Found the Wiki. Was unaware all of this already existed. Thank you for developing it.