Virtual DJ library/database import would be useful. Seems like the next one in line to conquer. After messing around with Mixxx, Traktor, Serato, and Deckadance 1&2 over the years, VDJ 7 & 8 are the only ones I still bother with to practice on occasionally or build some special playlist due to their amazing mapping ability, customization, and stability with basically all hardware.