Excessive general stain with staining developers can result from impurities in the tap water used to mix the working solution. Both pyrogallol and pyrocatechin (pyrocatechol) based developers are highly sensitive to water impurities so if you are experiencing heavy general stain with any of the staining developers you might consider mixing the working solution with distilled water.
Another thing to bear in mind is that the slight fogging of film that results from age or improper storage is amplified by staining developers. Remember that in the summer film stored in a closed car can easily reach temperatures of 130-40F and this by itself is sufficient to cause a slight fogging.
I am lucky to have a very good source of water for working with staining developers as I get a really low b+f with Pyrocat-HD, and only slightly higher with Rollo Pyro. This is with rotary processing.