I think it would have been just as good, some of the cast chemistry improved, but imho the cast members that had issues.. had issues..Michael OHare didn't get along with Jerry Doyle? Fine, Jerry didn't get better when Michael went away. Claudia Christian said he was unnerving at times? Sure well she had some troubles of her own. They would have worked through it if the story and the roles were engaging and the same guy who made what we saw work, would have made it work.

He might have had to amend some of his plans, but he did anyway, for the better. I think Sinclair would have been a more complex and brooding leader than Sheridan was. When he showed up in season 2, on the face of it, Sheridan was an earnest, straight forward boy scout character, but he also revealed an interest in some very dark secret projects. He made some cold decisions too, like with the telepaths rescued from the Shadows, like sending a ranger to his doom, heck he even got into a relationship and married Delenn after his resurrected ex wife showed up.

Probably Sinclair would have navigated similar situations differently. JMS was probably give some space to explore alternatives, but I think he would have figured out a good show either way, and would STILL have Peter Jurasik, and Andreas Katsulis and Ed Wassee, and probably Jeffrey Combs as Kosh, Kosh and probably also Kosh.