Less bitching from the players is the definite upside. Among the downsides would be limiting things geographically to too great a degree, stifling possible innovation, and simply placing too big a piece of the pie in one person's hands.
Emporia is the prototype for disc golf incorporating itself fully into a community and they run great events there by all accounts. Eric has done a great job imo of making the Country Club course the best it can be. I don't think there are too many viewers out there who are anxious to see a Major there every year on top of DDO however.
Everyone has their opinion. Your response though, solidified my position. It's primarily focused on "viewers".
An alternative option, however, is 5 or 6 superior "Super" courses being created and they are the predominate venues every year. Tennis & golf have very few venues for majors and don't suffer the "problems" you suppose.
Money may get infused into the sport and those super courses may happen in the distant future. And it wouldn't be a problem imho