Galvanic isolation between the servo side and the computer side
Firmware
Add bulk_read emulation support. Make it possible to disable emulation as it would be necessary if there are any MX servos on the line.
Pass every character through instead of retaining them. The servos should happily ignore any Dynamixel command that they do not understand…
Software
make a low level, performance-oriented C Dynamixel library that would support every functionality (including sync_read and bulk_read…) and multiple interfaces. Make it easy to make binding for (cf Dynamixel SDK).