Personally I would like to see each insert be a little OLED. Imagine a little display in every insert. Like the optimus keyboard (http://www.artlebedev.com/everything/optimus/). You have an insert for a random benefit, you can have that insert flash between all the random options.
It's not quite the same thing as a real honest to goodness pin but for virtual pinball I would like to see glasses free 3D and hi-dpi displays being used for the playfield. The pinball experience is all about depth and finally glasses free 3D can be relevant since you really just stand in one place in front of a pin.
I think the biggest tech upgrade wouldn't be in features to the game itself, but rather the underlying architecture. We should be thinking more Pin2000 and less old school pins. Going the route of a PC running an embedded OS as a dashboard is imperative to advancing pinball. A computer has way more processing power than the CPU boards ever did. They are easily replaceable (you won't be fixing a dead transistor on a CPU die but you can swap CPU's or motherboard, or ram easy using commodity parts. Internet (through wifi or ethernet) is imperative to supporting future pinball. Software updates are critical to supporting a game. Having machines internet enabled means an operator of large banks of machines can pull updates for everything effortlessly. Also networking would allow ops to pull audit logs in real time, maybe even post those logs back to a manufacturers web portal. Say an op logs into Stern.com and under their account are all the machines they bought from stern, they can view audit logs, test results, everything.
Boards should be simple, we should no longer be driving coils through hardware transistors. They should be connected through an interface board to the controlling PC and be driven by the software.
While on the subject of dreaming I would also like to see a headphone jack/volume switch located on the machine so in a room full of machines and noise you can still hear what's going on.