The problem with a series set at Starfleet Academy is that you will have to do completely different types of stores than Trek fans are used to seeing in a weekly Trek series.
You can't have cadets out saving the universe every week without jumping thorugh some pretty big logic hoops and/or straining credibility. I mean how often do we see cadets/midshipmen at West Point or Annapolis out solving problems of national significance or saving the world in a heated battle? You don't. they're in classes studying, and don't even have time for much of an interesting personal life for most of their time in the academy.
It may be possible to offer a Starfleet Academy series that airs exclusively online. I like the idea of having ony a few episodes, perhaps no more than six or eight at a time. Rather than focusing on a crew, the series could be built around a small number of cadets, perhaps one in each year of the Academy's program. These cadets could be followed through parallel storylines, occasionally interacting with one another, but otherwise having their own groups of friends and confidants as they progress through their studies. The series would therefore function as a sort of online TV diary to give the audience an idea of what being a Starfleet cadet is like.
A similar idea would be to have a series that follows cadets not only through Starfleet Academy but also through Klingon, Romulan, and Cardassian military training using the same parallel storyline set-up. Maybe the cadets could be brought together in battle later in their academy careers to tie the storylines together.