I actually see this is a good thing for Disney. Remember all of those Location-Based Entertainment rumors? This could easily be step one.
These parks were not built with the same show quality standards as a Disney park is. However, if Disney were to acquire the Busch family of parks, they would not necessarily need to rip out everything and start over. These are regional theme parks, and some of them (BGE, Sesame) only operate for part of the year. The Williamsburg property is never going to be a replacement for WDW, whether Disney buys it or not. It oesn't need to be; it is already successful using the current model. Going to Busch Williamsburg wouldn't be the same experience as going to WDW, even if Mickey was there. the Busch parks don't need to be "Disney's"-branded. Thus, in the eyes of most of the public, it's not going to be expected to be on the same level as a Disney Resort like WDW or DL would be.
Buying the Busch parks would be a good move because it captures some of the regional market and puts Disney in places it hasn't explored yet, like Virginia and Texas. They get to expand their influence into new regional markets without cannibalizing attendance at the big resorts. Think of it this way: Walt Disney Regional Parks could be a division of Walt Disney Parks and Resorts. Add to that the much smaller LBE hotels in already bustling tourist areas and Disney is doing very well domestically.
As for the parks that are close to existing resorts, like Busch Tampa and SeaWorld Orlando and San Diego... Disney could buy those as well, operate them for a while and then sell those parks off when the market improves. I wouldn't mind it if Disney bought and held onto SeaWorld Orlando, but it would be a logistic issue because if its distance from the core WDW property. The nearby parks pose a problem right now, but who knows, they might not mind controlling more of the market in Orlando and SoCal.
In any case, I think it would be a good idea. Not everything owned by Disney neds to be DISNEY'S necessarily, and I think this would be one of those cases.