shlind,
I believe it definitely falls under #2 (upgraded current features)

P.S. MTP Library was overall a very significant improvement, but the mechanism of searching/sorting part remained nearly same. My observation of a few topics on the subject... there are only 2-3 people that were displeased with it, citing very insignificant reasons that related to narrow workflow perks. I am strictly talking about Previous pickers VS MTP library. So yes, improving search / sorting would fall under "upgrade of current features".