While all this will make sense, from the perspective of a few, like some of us here, still most of the users will prefer either synth/workstation or arranger instruments. The market is specialized and a very narrow slice will really benefit of the combination. It just so happens that we are in that slice...

Those that use an arranger will use just few of the deep synth editing, just as the reverse is true, many synth players will have no or limited use for auto-accompaniment features.

I think this "bring together" can be done in the realm of software instruments, once one of the major players will finally introduce a completely software based arranger, like Dan's vArranger.

In my view, that will be the next major milestone. A software arranger, with sounds included, with all the editing tools needed for both arranger specifics (styles, pads, performances) and synth specific (deep editing, grooves, arrpegios, step sequencers, all that.) And that could be indeed modular, so you will only get what you need/want.

All this controlled through the convenient touchscreen interfaces and a simple MIDI controller.

There are many steps that were done already by various, but until it comes from a big name I don't see it becoming a serious alternative. Not because of lack of quality or features, but simply because of the trust that people need to gain in this. Nowadays harware can very well provide the bases for such a development - we'll see how long it will take to see it in reality.

On the other hand, obviously it will not be impossible at all to add to an arranger keyboard some of the features found in synth workstation, like arrps, we all know even some cheap Yamaha keyboards have that already. Hence my conclusion - it is not a profitable/wise move to unify these two, from the manufacturer point of view.

Again, we are only a narrow slice of the market... It will take a brave move from anyone big who will do this, and probably will take an innovative spirit, not a rational market decission.

I am thinking Roland... It seems they wouldn't have much to loose. They could play this big card and why not, turn upside down all the market.