I would also want an upgrade that can move the "unmovable" sectors, instead of just reducing their existence, that's boring.
It can definitely defrags slower there, or preferably shows some kind of extra animation there.
Maybe the animation is something about how the program goes into the registers & re-binds "pointers" (address locations) to the new file location or whatever?
Maybe it doesn't "solve" those "unmovable" blocks directly when encountered during the normal scan, but probably does an "initial scan" and solves them to the beginning of the file system, OR solves them at the end of the defrag, but that must probably need a re-defrag again, so it seems very inefficient, compared to solving them first.