What kind of games would you like to see once we release Prometheus? Would you like me to keep focusing on regular SGM games, would you like me to focus on Prometheus' (and remember this isn't the final name) advanced features, would you like to see more original games, more arcade ports? If arcade ports, do you prefer golden age (80-83), later period, or 16-bit stuff. We can go all the way from simple 8-bit stuff to Genesis/SNES level of complexity. Please let me know.
My only contribution is a tall order.
A lot of my favorites are those with unique inputs and outputs -- not just the 4 or 8-way joysticks, two buttons, and not just output on the monitor and speaker(s).
Also the ColecoVision's modular expandability was genius.
Spy Hunter is a good example. Audio is stereophonic. The steering controller needs not revolve 360 degrees. There are two switches on each handlebar, plus the "horn" button in the middle to call the weapons van. Additionally, that button has a built-in lamp when the van is available.
Gorf has external lamps based on your rank.
Q-bert had that solenoid inside that clacked when Q-bert fell off the cubes and hit bottom.
Sub-roc had a spinning shutter
I wouldn't ask for such unique controllers, but the potential for expandability should definitely be considered.
Enabling custom I/O devices that we could build ourselves would be cool. Maybe just a card edge connector like the SGM (and Atari module, and the Adam expansion) uses.
Perhaps also support for other classic and contemporary controllers besides the Coleco versions.