I got so sick of lugging that M9 brick around doing PT or going to the dining facility. Sitting in a vehicle with that huge pistol jammed into your side... Better than the M4 I suppose, but not much. That is a large heavy SOB for a 15 round 9mm...
Considering the competition weighs in 1/3rd as much, it should be a no-brainer.
Despite my previous mentioned misgivings, I don't think the military should switch. Why? Economics. We COULD do it inexpensively but we wouldn't. We'd piss away millions of dollars testing what we already know. There are better pistols.
We'll never move away from 9mm fmj, and that's just the reality. 9x19 is adequate, inexpensive, and logistics just work, and necessary for all the small people in the Army. Pure and simple.
IF the military just had some sense and did a low cost switch to another proven system, like Glock 17 or Glock 19, or Sig 226, etc, then I would say just do it!!!! Heck, certain units like Special Ops get Glocks and others like CID carry Sigs... why not big Army??? And I think a large number of CZ75s are employed in combat roles... that is a better, smaller and higher capacity pistol than the M9
But since any switch costs tens of millions of dollars in unnecessary testing then it's just not worth the cost. Pistols so rarely are game changers or life safers that a M9 or G17... meh they both get the job done. (Note, I did date an ex-Soldier female medic that was treating two injuried Iraqis when one pulled a knife and stabbed her and she shot him dead with her M9 and she got a purple heart - so it does work and get the job done.)