I currently play a Roland 700NX, I have had a lot of keyboards in my time most of which I would not mention. I have a C2 within reach too.
The Roland has spoilt me for touch. Its just a fantastic instrument touch wise. The Concert Grande is very decent straight from the box. The other Pianos are OKish, might go in this or that mix, but are not (IMO) goto. The Roland is poorly served by its tiny VDU, some, only some sounds are easily reached, the Synth is good average, no more.
I imagine this:
Imagine a robust non plasticky stage keyboard with 88 piano keys, build as well as the Roland. Each key also pressure sensitive.
Housed in this body above this, a Hammond Style, "waterfall" keyboard spanning four octaves, in the centre. Above this the Drawbars and essential Hammond dials.
To the left of the main keyboard a a pair of controller wheels, an input for a breath controller.
To the left of the "Hammond" interface, an area to provide synth control buttons - eight sliders and some generic dials. Each dial would be lit, and a small VDU would be beneath it to display its current reading.
Above, and attached to the keyboard would be the "music stand".
This would have a support stand for to USB connect a touch tablet PC of your choice. This tablet could be a standard Win or Apple tablet and it would provide an additional powerhouse for the keyboard
The Tablet could provide the following:
Notation Display (no more peering in the Dark)
Ability to Play VSTs
Normal Windows functions
Large clear graphical touch Interfaces for any loaded instrument
Internet connection if desired
Ability to Run a Sequencer of your choice
Packaged into the product would be ONLY instruments of the highest quality. No "almost made it" instruments.
These would include at least one example of each type of piano, each type of 'classic' organ (Wurlitzers, , harpsichord etc. Further instruments could be used from any manufacturer of VSTs.
Apart fro supporting VSTS, the synth section would not only give the "classic" synth sounds (which can be cheesy) but also there would be an ability to warp natural sounds (e.g. a real bee buzz). Introducing real world sounds (Omnisphere's burning piano for example) is key to getting at those wonderful sounds that occupy the top studios'
Special care would be given to providing USEABLE keyboard sounds. By this I exclude those Absynth like sounds that on the press of one key the sound goes on warping about for a minute of so. I mean those sounds that are "keyboardistic" (forgive the neologisms. Sounds that have a velocity variable attack, an intriguing sustain, and a useful decay. These forms of synth sounds can be very hard to find.
There are of course the group of bell like sounds, the natural bells andtghe warped bells, but there are also many other sounds that could be crafted and be both new and effective.
Inside the keyboard there would be an SSD hard drive. On this samples could be stored.
To the right of the "Hammond" interface, there would be a port for a mouse, a small but functional Alphanumeric keyboard.
Some assignable buttons for bringing up 'universal' presets, representing states of the instrument..
At the rear there would be ports to plug in a three pedal piano pedal set, a swell pedal and a footswitch - simultaneously! Of course there would be standard MIDI and Audio Ports. Additionally there would be a facility to plug in a user USB if desired.
Optionally, below, room to screw in optional robust legs. From these legs a bar could be provided to anchor the pedals so they don't move around. Cable clips for leads. Two types of cases, hard and soft, both with properly functional wheels
For me, such a keyboard would be all that many professional musicians would require. Provided it was built to the highest standard AND the sounds were top flight, it would sell.
I think that none of the current Top flight digital keyboards meet this criteria.
If you think about it, a Hammond does not really need to have Waterfall keys on its lower octave, this makes it easy to effectively combine the needs of a piano keyboard with those of a dual manual Hammond. The compromise is trivial.
Talking Hammond, there is nothing that really replaces drawbars, for their physical qualities. These may have to be motorised to bring up presets.
There are so many musicians that would pay for something that is RIGHT, an all in one package that is functional, customisable and upgradeable. Such a package would have to be versatile and with a killer intuitive GUI (the tablet).
Obviously building up to the highest standards in this way would be expensive, perhaps much more expensive than even the top flight keyboards of today. Maybe $8000 dollars or more.