I am of the opinion,that if Korg is going to top and out-do the M3's capabilities,they will have to increase production costs and raise their usual price tag a bit.
If you want a bigger screen,audio recording,more tracks,more insert effects and more memory,it's going to cost you dearly...especially if Korg plans on surpassing the Yamaha XF's capabilities(or even matching the XF).
Take a good look at the Roland Fantom G series....they tried to compete with the Korg Oasys by imbuing the G-series with a bigger screen(8.5"),24 audio tracks,104 midi tracks and PC DAW-like functionality...while also keeping the price tag relevant to the competition and in doing so,they cut too many corners and the end result was disasterous.
Only a $3,000 monster PC could handle that many tracks of the G series,most of the stock sounds are unusable and most users would not be able to afford $449 a piece for a f**king ARX card!

If Roland charged $8,500 for the G8,then it would be a fantastic synth.Any hardware workstation under $4,000 is going to have limitations,but even though the Motif XF does not have multiple synth engines,multi-track audio recording and a 10.5" flip top display screen like the Oasys,it does have a larger screen than the Korg M3,far more memory & expandability.
All this being said,I really think that in order for Korg to compete with the XF-while still remaining in a similar price range,the next Korg flag-ship will be the most expensive workstation to date(outside the cost of the Oasys).
I must say,that having done all the research I've done lately on the Yamaha's,I've grown into quite a Yamaha fan myself and I think that the Motif XF is one of the most fascinating workstations ever conceived,in this price range & certainly the most advanced!
-Elwood