but you have to manually adjust/tweak the grids in traktor to get them perfectly in time. the algorithm is now pretty good but in my experience it's not 100%, same with rekordbox, it needs a bit of manual adjustment which is saved with the file. with cds, you can't tweak the settings and save them so you run the risk of the bpm detection going haywire. a loop drifting out of time in a mix has far great consequences than an echo delay drifting!
i just don't think there's a realtime beat detection system out there that's 100% accurate like a manually set beatgrid which is why pioneer devised rekordbox.
i hear what you're saying but i just don't think it's technically possible. a good halfway house would have been pioneer allowing you to burn a 'rekordbox cd' which saved the beatgrid/waveform on the disc but that's not really what you're after i guess!
i'm pretty sure you can set up even the current cdj2000 to save waveforms to sd/usb from audio cds just like you could on the cdj1000 if that's any help?