Disney had already designed it for DCA, WDW didn't have anywhere better to put it and it'd been awhile since DHS had gotten a new attraction, bam. Toy Story Midway Mania in DHS.
Yup, that's about it.
It was a Jay Rasulo thing, when he was Parks Chairman in the mid 2000's. He doesn't get theme parks, doesn't have much love for them, and very rarely visited them when he was Chairman. WDI had designed the ride specifically for Paradise Pier in DCA, to slot in on the midway right next to the Games of the Boardwalk midway games. Midway Mania got a custom façade that played up the new Victorian/Edwardian theme of Paradise Pier, and it slots in perfectly in that location because originally that was the only park that was going to get it.
With an indoor/outdoor loading area and Mr. Potato Head acting as the midway barker heckling folks as they walk by.
The Games of the Boardwalk next door to Midway Mania also got a dramatic retheme and upgrade in 2008 as part of the project. Midway games leading to Midway Mania, it all makes sense!
For DCA, this was a radical upgrade to the park when it opened in 2008, and it hinted at what was to come in 2010-2012 as DCA underwent its huge 1.2 Billion Dollar extreme makeover during those years. Midway Mania at DCA replaced an ugly, cheap corner of the park done by Paul Pressler as it opened in 2001.
To go from this photo below to Midway Mania was quite a pleasant surprise, and more changes were on the way for DCA!...
Future Site of Midway Mania - Paradise Pier fast food and cheap stucco walls circa 2001-2006.
But as for Midway Mania's place in DHS? That's a tale only Jay Rasulo and some clueless marketing dorks could enjoy. At least it added a very good ride to a WDW park that desperately needs a lot more rides. But it was a very good step in the right direction for DHS. Interestingly, those steps stopped after '08 and DHS has gone back into a long term holding pattern shrouded in mystery.