Yes I think that soft synths have a bright, a very bright future ahead of them, It would be great to have one keyboard as a host (with a dedicated OS), running various softsynths on it, and a new system, like a basic set of controls that every softsynth host has, including arranger controls.
Imagine having various "virtual arrangers" in your host keyboard, just buy one host keyboard, and you can turn it into a synth, a digital piano, an arranger....whatever.
You don't have to buy various synths and modules just to get a new soundset, you just have to insert a cd, install the software, and have a brand new synth.
No more need for buying more hardware, just one machine .
I'm looking forward to it.

Greetz ,
Marcel