A couple things that I think get lost in the offseason optimism:
One is the usual projection and optimism. Someone sees a highlight video with some nice plays, and imagines the player making those plays all the time, and compare that to what they expect other teams will have. Or worse, imagining them being better than their best plays while adjusting to the college game.
Another is looking at players in isolation. Sure, we have a nice class coming in, but how does it stack up to the competition? Look at other highlight videos of the recruits that are joining us in the BIG. If you go by recruiting rankings for this class, there's a bit of a drop-off after the top 6 in the conference:
1 Maryland
2 Indiana
3 Michigan
4 MSU
5 IL
6 tOSU
Being in the top 6 is nice. But consider that we have significantly more turnover than probably any team in the conference, and that drops our best case scenario to be more like middle of the conference, barring a miracle of catching up immediately to teams with better or more experienced rosters.
I'm ok with wild optimism for the future. Just don't see a reason to believe we'll be equal to or better than the upper third of the conference in the coming season.