What if it was bumped to 32 characters?
I agree, just a little bit would help alot. 32 is the next 2^x after 20, so I would think a logical progression.
Of course, this is something that would be nice, not needed, so if it is difficult to enact or would take up too many resources, I obviously understand.
Still, one of the nicest things about FR is the ability to do powerful research with it via keywords, and this would make that tool slightly better...