If I had my way?
-Nanoha, Fate, Tia, and Subaru take center stage again
-The less interesting characters (Elio, Caro, Lutecia, Otto, Deed, Dieci) get the Yuuno/Arf treatment
-Arf stops getting the Yuuno/Arf treatment
-The Velka Knights and Hayate stick around
-Ginga and the better Numbers (Wendi, Sein, Nove, Cinque... Wendi watches over Nove, Nove is attached Cinque, and Wendi and Sein are apparently good friends, so it works out) join the main cast
-Twisted villains that aren't open for befriending, much like Scaglietti and Quattro.