There is nothing concrete that you can provide right now that will show clear differences between the two teams. But, I'd argue that the offensive staff, system, and depth is far superior to 2016 and that makes a huge difference.
1. Offensive Coaching: Day, Wilson, and Yurcich are leagues above Warriner and Beck at putting together a game plan and adjusting for future opponents. More importantly, Day is committed to an offense that provides a variety of looks to a defense, compared to Meyer who struggled to successfully graft new parts to his old concepts.
2. Fields: Obviously not as experienced as JT, but I don't think you can stress the importance of having a QB that can make all the throws while still stressing a defense with his legs. He'll make some mistakes and his nerves are still showing at the start of games, but he will make up for it as time goes on with the enormous growth potential he gives the team.
3. WR/RB Quality & Depth: Curtis Samuel was a phenomenal player, and Weber was really good for a RSFr. But I'd argue that offense didn't have much beyond them. 2019 has 3 senior WRs, a better pure WR than anyone on the '16 squad in Olave, and a great veteran RB in Dobbins. And then you still have Teague, McCall, and Wilson who are still coming along and are already contributing to every game, and not just in garbage time.
I totally understand why people are skeptical, but we'll probably just have to wait for Nebraska and Wisconsin to have a good understanding of how far along this team really is and what their ceiling might be.