As long as the show doesn't turn into a garbage fest I'm cool w/ staff changes. Considering that the people in charge of future stuff have been part of an extremely well rounded and talented team for a while I don't actually see a decline in the quality of the show coming with the changes in staff.
Also, keep in mind that people like Renzetti and Faust have their own original projects that they would like to work on. And while it was a very nice experience for them to work on ponies, as artists and professionals, they would much rather work on their own projects (like Galaxy Girls for example).
EDIT: Sweet drawing Geodude!