Mdd,
1. Not at all. Any leader must be acceptable to the public
(Berachot 55a). If it is an obligatory mitzva why did they wait 355 years? Why did Gideon refuse to be king? Why was Shmuel unhappy with their request? For that matter, Abarbanel prefers a republican form of government and effusively praises the systems in Florence and Venice in his time. According to Rav Kook (Mishpat Cohen 144?14) that any leader accepted by the people has considered a king for his functions it is not a problem. The mitzva is to appoint a national leader. If he is a king he has certain dinim that a judge or nasi does not have.
2. True. However the number of qualified people today is certainly very large.