If Kansas City wanted to change its' fortunes, it needs to rezone Paseo West downtown, and redevelop the entire area into a dense, mixed use district like is shown in the Union Point Youtube videos.
It's very difficult to place 8 million sq. feet of office space in the East Village of downtown, and also have to deal with employee parking. Our mass transit system is not robust and well-established like many larger cities. Not all Amazon employees are going to want to live in apartments downtown.
However, if you took the East Village and combined it with Paseo West, you might be able to incorporate that much office space and new multi-tenant housing to handle Amazon. It would require a larger streetcar system, and probably a commuter rail system be in place (which isn't now). It would also require a citizenry willing to allow such a streetcar expansion. Keep in mind that there are many that still actively oppose streetcar expansion.
Kansas City is too far behind the ball to land Amazon. Maybe in 20 years it could have--if all the above were in place.http://www.kmbc.com/article/recent-ranking-of-potential-headquarter-sites-puts-kc-near-bottom/13054873
One more thing to keep in mind with any location Amazon picks. I believe there will be some consideration given to the political climate. States that are hell-bent on fighting culture wars: religious freedom laws, bathroom bills, outlawing abortion or access to birth control, and finding ways to deny minority civil rights are probably not going to get considered. https://firstname.lastname@example.org,-94.5664115,1349m/data=!3m1!1e3