Mdd,
1. Abarbanel is a Rishon. There is also the statement in the Gemara (Berachot 55a) that a leader must be acceptable to the people. It might even be that they can recall a king (Yerushalmi Horiot 3,2 and Rosh HaShana 1,1 with Korban HaEida and Pnei Moshe there and Responsa Avnei Nezer Yoreh Deah 312,15, Rut Rabba 5,6 but see intro. to “Oneg Yom Tov” )
2. Who says that one cannot argue with Rishonim if he has solid proofs? See http://www.theyeshivaworld.com/coffeeroom/topic/arguing-with-rishonim-and-achronim.
3. You still have not answered my questions regarding the kings of Israel, bad kings, Hashmonaim and Herodians. For that matter, why was the leader after the Churban always called the Nasi?
4. How does the Netziv allow a postponement? What if no generation would feel that it needs a king? He does not mention any time limit. In fact, it took 355 years to annoint Shaul.
5. It is outrageous that you dismiss major poskim with a wave of the hand. You must go to their graves and beg forgiveness with bitter tears.