I get the feeling that Disney is held to a "darned if they do, darned if they don't" standard by most people. If Disney goes a few years without producing an E-ticket attraction, most people cry foul and swear that they're going to Universal instead. When they do replace an older, lesser-attended attraction with a new one, they're called to the mat by the purists who refuse to let go of even the smallest bit of nostalgia.
SE rarely has a line and, even with several updates over the years, has gotten a tad stale IMHO. Why not replace it with something that people will actually line up to see and/or ride?
I love most things Disney and have seen a few of my favorites over the years go to seasonal operation or go away altogether (Timekeeper, 20K LUTS, Horizons, etc) but I understand why they're gone.
For several years now, we've all been complaining that Disney isn't what it once was. Now, after several announcements (and rumors, hence this board) such as Expedition:Everest and Time Racers, people are still upset -- "Disney scrapped the pre-show", "Eisner slashed the budget" and so on -- before the attraction even opens or, for Pete's sake, before ground is broken. I'm not sure how we can judge the atttraction or possibly know (for sure) how something will turn out until we actually experience it.