I gather Lutz’s claims (if he even wrote the article) that WDW was foolish to announce a 12/5 opening and that it will be a disaster at opening were an exaggeration. It’ll have issues and downtime like any new ride but should be ready to open. I wouldn’t expect anything more clunky than Hagrid’s opening season, certainly.
I always got the impression that folks at that other site, VerminTalk, were jealous whenever WDW got anything that could be deemed as preferential treatment and took it as an opportunity to smear WDW. There’s no question in my mind that, for SWGE, we got the superior product and rollout. They win on Marvel, though. If they don’t cut phase 2.