Re: Worst WM Main event of all time
The answer is probably from something pre-1998 but I don't really know anything too well to comment on those. Instead I'll just pick the worst ones from the past 15 or so years.
The Miz vs John Cena - WM27 (BOOOOORING and even The Rock's post-match involvement couldn't save it. Doesn't help that it almost ended by a freaking countout.)
Triple H vs Randy Orton - WM25 (Don't think it's nearly as bad as most say it is but yeah, it was very underwhelming with the dead crowd and lack of heat despite the intense storyline. Glad that Orton finally main evented a WM, though. For that alone, this wont be my pick.)
Triple H vs Chris Jericho - WM18 (Crowd wanted Hogan/Rock and for that reason, putting this match last was a big mistake. Completely dead crowd and just very boring to watch.)
Best main event is easily between WM20 (Benoit/HHH/Shawn) and WM17 (Rock/Austin).
Also don't get the hate for Rock/Cena. I think it was pretty decent and the finish was great.