Would DS9 have been better if the Dominon War ended sooner?
I don't know. I liked DS9's finale very much. But for the sake of speculation ending the war sooner would've given the audience a chance to look at the aftermath of the war and the admission of Bajor into the Federation. I wouldn't have minded if the war had ended around the middle of Season 7 and leave the remainder to deal with the aftermath. Rogue Jem'Hadar or Cardassians could be antagonists if that was needed.