Wouldn't that cause rank 5s to have a huge advantage over rank 1s?
P.S. Also needed: [Hosting more options 2] Add option "Same rank with you"
That's the answer
Or I've got one more idea with rank difference(that doesn't cancel hosting option about same rank): [Server access by rank] Several server are made for different ranked players
Friend list is the most important part of the game that need to be made (in my opinion). Also being able to see what they are doing and what game they are playing is good to. A clan option or the ability to add a clan name to your name.