Correct, one of the major 2018 themes was Rod Smith, but that doesn't preclude him being a big part of Illinois' success next year. This would be different if Illinois had a senior QB (2013 Scheelhaase) or a lot of returning well-known players (2008), but this is still a fairly unknown offense that did really well last year.
Plus, I am thinking our defense will improve similar to the way the offense improved last season. But I still believe the offense will be the story and will see a considerable bump depending on health