WOK has that magical "it" factor. It's inexplicable and works just because... Under any kind of scrutiny, it really stands-out as a haphazardly made film. There are huge plot holes and gaffes. But I think it was almost saved by the low budget and lack of resources (and little amount of time he had to rewrite the script). Meyer had to keep things moving at a snappy pace out of necessity. This doesn't leave a lot of time for things to fester, so the audience can then stay in the moment--and each moment is a lot of fun on its own.
Take the prefix code for example. Think about it for two seconds, and one finds it's a pretty ridiculous concept and total travesty of a DXM. Yet all that gets lost in the drama of the moment. Same goes with Genesis's creation. How many people realized that it totally contradicted the premise stated earlier in the film on their first viewing? I'm sure there were a few, but most people were probably still teary-eyed and reeling form the shock of the previous five minutes and couldn't be bothered.
Also, a lot of the dialog is rather trite, but Shatner and Montalban's performances transcend it. In fact, I think either performance makes for a great microcosm. By any critical standards, neither is very good on the whole. (Each has a great moment or two.) They're both over-cooked ham. Yet there's just something about them that's fucking awesome and memorable.
Take Montalban's reading of "I'll chase him..." for example. Meyer just took a famous line of classic literature, altered it a little to fit the scope of the film, and pasted it in. It's a cheap shortcut--the kind of thing one does on a paper his freshman year. And taken out of context, Monty's reading is way over the top. Yet it just works.
Compare that to Chang. Meyer did the same thing. And, by any other standard, I think most people would agree Plummer is the better actor. (The guy is one of the best ever.) But all of those lines of Shakespeare just feel dead, and the gag quickly gets annoying. Because that it factor isn't there.