I noticed that when quoting Rishonim, Beis Yosef/Nosei Keilim tend to focus on Poskim (Rif (and main commentary)/Rosh/Rambam, Mordechai, Teruma, Rabbeinu Yerucham, etc.) and responsa.
Very rarely do you find "Chiddushim" seforim (like Chiddushei Rashba, Ritva, Ramban, Peirush Hamishnayos of the Rambam [except in Mikvaos], the Rash [ditto]).
Why is that? Tosfos are still fairly commonly quoted but no "Gemara peirush" since then. I would assume that the Rashba's explanations of the Gemara could bring Nafka Minas to the table. If it's because it wasn't written as a "psak", well, neither was Tosfos.
Very rarely do you find "Chiddushim" seforim.
I wouldn't go that far at all. The Beit Yosef, for one example, cites them with some regularity - most especially the Chiddushei HaRashba. – Fred Mar 10 '15 at 2:40