He has grow, and that should be expected in year 2, and I think he is getting better game by game (starting in the 2nd half of last season). But I think the one huge factor in the statistical success you highlighted in the first two games this year is the improved o-line play = better protection and better results in the run game.
When one reflects on it, it's a miracle this team won 6 games last year with the offense of players it had. Every aspect of the offense has improved, from QB to the line, WRs, TEs, and backs.