What about the bridge crew (Sidney LaForge? T'Veen?) What about Dr. Oake? Who's Chief of Engineering? Plenty of new characters there.
You would shove Seven into the background to work under a relative stranger? (A relative stranger who's a world-class cad.)
Worf came to DS9 when it was already established (Berman thought that Sisko needed another black man to talk to.)
Bear in mind, this show had Brian Bonsall playing Alexander in blackface. (It's one reason Disco went with the purple-skinned Klingons. Kurtzman didn't want the actors' skin colors being an issue.)
We still have seven episodes to go here. To put Seven through all this crap only to tell her in episode ten, "You're
STILL not good enough to be Captain" would be cruel.
If it were up to me, we would not be having the Nemesis Atonement Tour.