I had a similar isue when I bought the XDJ700. So after Pioneer converted Recordbox to a performance software they seem to band other DJ software from more and more of their products. I think is a mater of Pioneer, trying to convert more and more people to Recordbox ..
Serato DJ needs to add HID support for XDJ-1000MK2. I mean the XDJ-1000s have it, I can't imagine it would take too much development time to integrate XDJ-1000MK2. This would obviously take people away from switching to Rekordbox, which is Rekordbox's ultimate goal. User retention is key at this moment when there is more competition on the market.