I would like to see a series set in the 25th century that focuses on a fleet of ships. The major arch of the story would be an Admiral on his heavy-battleship organizing the defenses of the federation's borders. Side stories include (but are not limited to); an exploratory vessel (a solo heavy-ship) seeking new life and new civilizations; a small fleet comprised of a Defiant-like destroyer, a Voyager-like advanced scout ship, and two cruisers (red shirt(s) for a two-parter down the road) and their missions would involve escorting or reinforcing; a small diplomatic/aid/disaster relief fleet comprised of a heavy ship (a galaxy class if it were up to me), a medical ship, a frigate, and a scout ship and their mission would involve offering assistance to those who need it; and a highly-advanced ship (maybe two or a Prometheus-like multi-spliting ship with a captain and his two commanders) dealing with internal affairs (starfleet intelligence maybe).
The first episode would be the Admiral addressing all the captains of their missions. They'll separate into their groups and later episodes will follow each point of view of the captains as their story unfolds. Later, in a two-parter/season finale the fleet gathers to prevent an invasion or something. The series would end around an assault on another faction that plans to bring an end to the federation (the Dominion, or the Borg, or some new one) and the fleet we follow is met with other Admirals and their fleets for an all out battle. Sprinkle a few guest star ship/fleet episodes, space station episodes, and a colony we catch up with time to time and you have a galactic Star Trek series (and a financial nightmare).