its a tough one for Ducati as high miler bikes like GS's are cheap to run and service and have high residuals i know some on here aren't bothered about that but to tempt BM or KTM riders away servicing costs and residuals have to be comparative. I'm not sure whether it needs to be off road capable, I'd have said not after owning 2 multis but now I'm starting to ride the GS on trails its opened up a different aspect of biking and would look for this ability on my next purchase.
I can't see the water cooled engine offering any real advantage, getting the rad and front cylinder in the line of fire from stones isn't what i'd want, surely an air cooled engine is easier and cheaper to service as well? If you are doing reasonable mileage on this type of bike low service costs are really important and anything that reduces it has to help.
Design wise it needs to take ideas from others - simple stuff like a centre stand that works and doesn't ground, panniers racks you can leave on and look like they are meant to be there, heated grips with the control on the handlebars not the dash panel, info computer operated from switch gear not stretching forward to dash, adjutable height and angle screen and adjustable seat to fit more rider sizes or simply being able to swap seat height during a trip. Most importantly for me a shaft or belt system, if its not going off road ditch the chain and have it on belt, i hate lubing chains or having to fit a Scottoiler

dual power outlets, space for GPS designed into dash layout so it doesn't obscure clocks. Pillion seat removable and then flush to top of panniers when fitted so you can fasten wider bags across that area supported by the area below seat and the panniers. Height adjustable and removable pillion pegs and plenty of space for pillion if possible. 20 - 25 litre tank for getting round the north of Scotland on a Sunday

No stupd indicatrs in mirrors, too expensive to replace, platic around seat/tail unit should be easy to replace and cheap, its easily damaged if you fit throw overs. Air/coil suspension so you can increase spring rate easily for heavier loads by increasing air pressure, i like the idea of ESA but its too complex and heavy. Hugger/spray guards under seat to stop crap getting thrown sideways and keep rider/pillion dry.
Phew, I've got loads more on a wish list but you are probably bored by now
