It was night and day when he came in. The show went from mediocre and not what I wanted out of Trek prequel show to just outright bad with the Xindi arc, but then came back to be exactly the prequel I wanted. It even fixed earlier seasons with its 3 episode Kir’shara arc that explained why Enterprise Vulcans seemingly became antagonists that eschewed things like mind melds and other familiar aspects of their culture.
Then when they canceled it, they got rid of him and gave us a truly awful finalie that crapped on the show and everything Manno Coto built.