Here's the list of receivers he's had to share snaps with
Chris Olave (1st round)
Garrett Wilson (1st round)
Smith-Njigba (1st round)
Marvin Harrison jr (future 1st round)
Emeka Ebuka (might return or possible 1st round)
And he came in the same class as Jamison Williams (1st round).
He was never their number 1 guy but the fact that he's seen as many snaps as he did has to say something.
It's a double edged sword though - with all the attention on those superior players, should have left him open one on one a lot more to be able to get open and have more impressive results.
Again, I think Fleming is an improvement and I hope we do indeed pull him in, but I'm not convinced he's significantly better than other "talent/upside" guys we already have.