Clearly the offense was built around the run game and PA pass. That was the identity and the rhythm method that worked so well. Now the OLine isn't good enough to support that. Period.
Even if TGIII is done it shouldn't matter all that much if the OLine could still function. We have other backs who can run and catch, as well as a good QB and quality receivers and TE's.
McV's offense just isn't working with a bad OLine. Most don't. However, so far any attempts to find an offensive identity that can be successful with bad OLine play have failed.
Like others have mentioned, i think he's got to mix in a balanced run game with a quicker passing philosophy.
Even when the run game struggles (which it has and will continue to with sub par blocking)....find a way to establish rhythm by just moving the chains more deliberately and only take the chunk plays when they come instead of forcing it.