^ The Lakota was a beast so you can update an Excelsior to be a top notch combatant. We know that Admirals in the past have used Excelsiors as a flagship, such as Admiral Nechayev using the USS Gorkon in 2369.
But that wasn't during wartime. And not every Excelsior is that upgraded. Besides, I don't see Ross as an Excelsior kinda guy. Excelsiors are for prissy admirals, which he wasn't. I could picture him on a Nebula or Galaxy. Though an Intrepid might be a little too small/sexy for him.