Currently we have no control over how often processes switch from one to the next. I have seen cases where processes print 2 layers before switching to the next, which is not good when doing dual extrusion.
When doing dual extrusion it can be beneficial to limit how long each process can print for.
For example, if you are printing a black and white checkered pattern that takes up nearly the entire build plate, with each layer taking several minutes to print, your black or white filament which is not currently printing is bound to start drooling, making your print look horrible. Ooze control can help, but only to a certain degree. However, if you can control how long each process can print for before it switches to the next process, then you could prevent drooling more easily.
For example, a "Process Switching TImer" value of 10 would limit each process to printing for only 10 seconds. Once 10 seconds are up, the process pauses, and the next process starts printing. That process prints for up to 10 seconds, then it pauses and the previous process continues from where it left off, and so on.
If the value is low enough, it could be possible to do dual head printing without the need for a purge wall.