Me, and a lot of my friends, often accidentally choose and paste a wrong nick when using tab-completion and then go like "oooh stupid tab completion!". I think a lot of frustration in that respect can go away when the nick list the tab completion uses can be sorted (as an option) on who last spoke in the channel. After all you are usually replying to what someone said just before you.
So if there are two Nicks NoEscom and NoAscom, and NoEscom spoke last, tab completion would producr NoEscom first instead of NoAscom. Any comments?