IMO, nothing would be more disappointing then to see the Royals do something like move/build a stadium near the race track. If they're going to do that, then just refurbish The K and be done with it as far as I am concerned.
KC is not the ATL metro, the Royals artificial city will just consist of more chain restaurants and chain stores. It works at The Battery because ATL is huge and is still getting a massive influx of newcomers and transplants, and has a much larger corporate environment.
KC needs a downtown boutique ballpark, or just don't bother.