I will stir the pot a bit.
First and foremost, this is a new and fairly complex offense, so it will take a bit to get used to. You should be looking for improvement from game to game, not an instant, explosive offense.
With that said:
Michigan's wide receivers don't impress me, and haven't impressed me in quite some time. For all of the OMGSTARZZZ they seem to get, their wide receivers always seem...pedestrian. Every year their "talented wide receivers" get a lot of preseason hype, only to fizzle out. Michigan's highest ranking wide receiver is 24th in the B1G. In 2018? 14th.
Also, Michigan media, stating a guy's name doesn't make him good. OMG NICO COLLINS. These guys aren't known to anyone outside of Michigan because they are thoroughly average. Let's try and put a little analysis into it before we just mention a name and expect that to be good enough.
Michigan's running back situation is actually worse than their wide receiver situation. For a helmet school, and the amount of OMGSTARZZZ players they have recruited in these two positions, the results just aren't there.
I think most fans would agree that Michigan has needed an offensive overhaul for awhile. However, this is a lot more complex than just plugging in a new system. They also lack talent & coaching at the skill positions. Gattis will help with both, and I expect to see steady improvement this year.
In conclusion, expecting a huge offensive leap is a bit much. Look for consistent improvement and player development.