I enjoy most of your origional post, but I have to disagree with you on this one. The thing I love about M:S is it's immersiveness and easy to follow story. In my opinion, M:S has done a better job at creating that over-all experience than almost any other attraction to come out on property up until it opened.
You begin with an interesting queue; from the giant "wheel" to going by "mission control" it is informative, sets the mood, and serves it's purpose. You then move on to a preshow that also sets the mood and delivers the basic story. Moving on again, you get a second preshow that delivers the safety information while at the same time sets the mood even more and gets you pumped as you are assigned different positions. Finally, you go on the ride itself. It is well done, extremely immersive, and lives up to the hype generated by the preshow(s).
I think M:S is a very well done E-Ticket and I would never consider it to be "mediocre."