Space Mountain succeeded because Disney took what even at the time was a tame coaster experience and dressed it up like no one had ever seen before. The thrills came from the environment, not the towering 2-story drops or the screaming 28mph top speed.
Call it want you want. The thrill came from it being a "coaster in the dark". The open air atmosphere and the glorified planetarium skyline were not the main attraction but they do add that "something more" WDW tries to emphasize. If there were no dressing on it at all people would still flock to it in droves, because it is one of the few attractions with any type of speed at the Magic Kingdom. (even if it is only 28 mph)
The dressing-up job shows all the signs of being a video-game. Both the focus and the dressing-up of Mission:Space target an audience of teenage males, not because of a successful tradition within the Company, but because it would make a good advertising campaign against IOA.
This implies WDW is recognizing its competition and attempting to respond to it - something they have had the privilege of avoiding for decades. M:S will not be enough for a teenage male to spend his money on. There must be another reason for the investment - space and speed are attractive to alot of people and will certainly boost Epcot's ratings.