I think this could be more interesting if it was a superset of C++ that allowed for brevity in some cases. Something that could:

1. Act as a preprocessing step for any existing C++ file

2. Output perfectly servicable C++ in the case where you want to move away.

Additions like the "known" keyword make this look badly thought out.

In any case, the weakness of C++ in most cases is compilation speed, not typing speed. Even in the ideal case I can't see this adding more value than it detracts (preprocessing speed + buildsystem complication + extra dependency).