Unlearning partial skills should clearly be available. Assuming this is in the works, but starting a new thread here to catch others running into the same situation.
See here in Ideas as well: http://www.glitch.com/forum/ideas/13395/
This is exaggerated now that I've unlearned some of the skill tree under one of the partial skills. I have Herbalism 2 partially started, and (I think) still counting against my total skill penalty. Meanwhile, I've unlearned H1 and BS, making it even stranger to have H2 sitting there at less than 10% without two of the prerequisites.