I know that the whole "ONLY MUSTANGS GET TO BE OFFICERS, NO MORE HOIGHTY TOIGHTY MILITARY ACADEMIES" is a popular thing thanks to Bob Anson's ode to unrestricted nuclear testing, but is it really that smart of an idea for an actual military.
I mean, let's look at it. Yes we should allow talented and experienced enlisted soldiers who have the talent for it to go through some form of OCS( Which, I might add, Nepleslia actually lacks), but we also need talented and experienced enlisted soldiers to serve as NCOs. And then there's the fact that if your only new officers are mustangs, you're missing out on the youthful and college educated crop of young officers you get from an academy such as West Point or Annapolis. Not only would such a college teach and prepare newly comissioned officers the basics of leadership and how to be a proper officer, such a facility would also have the added benefit of teach other military related sciences to these cadets and thereby making them more well rounded individuals who bring a different viewpoint to the table than just Mustangs.
You are distinctly overvaluing the contribution most officers make to their unit. Imagine life in a military unit as a set of tasks that need to get done in a day, seven days a week, 365 days a year. Paint needs to be chipped from bulkheads. Maintenance needs to be completed (and signed off on). Equipment must be validated and inventoried. Parts have to be ordered. Unit paperwork must be completed, sometimes in duplicate, usually in triplicate. Training must be conducted. And occasionally, sometimes, a bad man threatening the country you serve has to be shot.
Military sciences, war theory, gentlemanly conduct and the smattering of collegiate-level education that an officer's academy provides does nothing to accomplish these tasks in a unit. It doesn't even come close to preparing the junior level officer for the stark, harsh reality that he is not special, that his academy ring means literally nothing, and that he has almost no power or knowledge and tons of responsibility for making sure everything I listed above (and lots, lots more) actually gets achieved.
Different viewpoints mean nothing. In the military lens, the only viewpoint you need to have and have the energy to maintain is that of accomplishment of the mission. Anything else is not doing your job. You may cite mavericks that ultimately turned out to be right in their opposing viewpoint as examples to prove me wrong, such as Billy Mitchell, or outstanding officers that came from such academies, such as General Patton, but these men are outstanding exceptions to the rule, rather than the norm, and what makes their unique contributions valuable do not need to be replicated constantly in the average unit of rock washing, parking lot vacuuming garrisoned servicemen.
As for mustangs, mustangs know the enlisted side. Mustangs are intimately familiar with the way a typical unit works, and what it requires to succeed. A junior officer is not going to know things that make life for a unit easier - like when to give his personnel liberty over a holiday period while still maintaining a rotation of people to ensure work continues to be done, or just which supply depot chief to needle (because hey, remember chief, when we were both dumb privates and I saved your hide that time? Yea, I need a favor...) in order to get an essential part that is required for the unit. Mustangs bring invaluable tactical knowledge and working experience to bear when put in leadership positions that academy officers can simply not demonstrate. Strategic level leadership can be learned on the fly. It is the day-to-day running of a unit that is the truely valuable, practically irreplaceable knowledge that gives the unit with a mustang the advantage over a unit without.
In a unit, it is the junior officers without prior experience that can be lost with the least loss of capability. In the staggering majority of cases, they can be replaced with Senior NCO's, who in real life, typically have to babysit and mentor the junior officers assigned to their unit anyways. Nepleslia has made the decision that they want their officers to support their enlisted men, not the other way around, and in this, I feel they are ultimately correct, or if not correct, than at least on the right track.