If it will be adults only, I too would recommend the Sheraton Suites on the Country Club Plaza (the world's first shopping 'center"). So many great restaurants and shops right there at your feet. Best BBQ on the Plaza (IMHO) is KC Masterpiece. However, for character, try Gates BBQ. There is one located on Main Street between the Plaza and Downtown.
All the rooms are basically the same at the Sheraton Suites and I don't believe I have ever been upgraded to anything there.
Avoid the 4 Points. It is really not on the Plaza.
With regards to the Westin Crown Center, I would advise working directly with the front desk if you call for reservations to get an upgrade. Finally, not to split hairs, but the piano is in the "Royal Suite" and not the "Presidential Suite". My favorite room there for views and layout, however, is the "Liberty Suite".
Finally, I do believe there is a bus that leaves the Westin for Royals games and cost $3 or so. A real bargain.
Go Royals!
[This message has been edited by PLangian (edited 04-15-2002).]