As far as I know, there are no current plans to add this functionality to MatterControl Sync. However, I'll be sure to let the developers know. As a workaround, you can always upload a .gcode file with the commands you want and then "print" it.
We're also working on another product right now which might interest you, which will be called MatterControl Connect. It is a WiFi dongle that you will be able to plug into your printer, and then be able to control it remotely from your computer as if you were plugged in through USB.