I just had an idea - if RekordBox had the option to automatically play songs in the same sense that iTunes does it would completely replace iTunes for me as my default music player. It could be an option you could toggle on/off, but to have the option for it to automatically play the next song once one finishes (in a playlist or whatever you're searching) I think would be handy. Not sure if Pioneer wants to go this route, but I think it would be cool :)
Also, I find it pretty annoying that if I search for something and delete a song it clears the search - what if I'm searching for specifics of songs I want to delete? Would be handy if the search stayed there as well.