Well, I guess they could release an updated MD mkIII, why not. The mkII is now several years old, and even if this is still a good machine, some new upgrades could be interesting like things available in the A4 : multi-scales, mute trigs, Performance mode, patterns saves, keyboard record in Midi In, USB etc... and a black front cover
This will probably not require a big budget for development, will give freshness to sales, reposition the MD as the top notch of the drum boxes, and without disturbing their range philosophy by introducing a totally new drum machine. In fact it is what they did from the mkI to the mkII.