You'll only get people annoyed by making suggestions 'out of boredom'. Needless to say, the team can't use Half Life as a standalone engine, because they would need to pay money for the engine. That engine can only be funded if they receive money for their work. Receiving money for their work would only increase the chance of FUNimation stopping this mod. Think before posting.
Settle down, kids. Jedi, the suggestion has been made many times before and is simply unworkable. We do not have source code access to HL, only the SDK. Being standalone would likely piss of funimation and other interested parties as we would be in direct competition for paid games. So lets all chill and let it go.