To be fair, this became incredibly difficult to implement when Lemur moved away from their hardware device, computer/tablet screens become so diverse, and keystrokes/mouses (mice?) increased in complexity. It was actually available on earlier releases, but focus shifted elsewhere...for example custom graphics, which is far more useful. Who wants to use Lemur to type!?
Both Logic and Cubase have MIDI assignable macros. Use MIDI.
Doesn't AutoHotKey have MIDI to keystroke? Maybe that will suffice.