I don't see any unreasonable expectations for Jasson above. Especially since most of them seem longer term past this season.
But I won't back down from Lewis not developing much at all.
He's a guy who doesn't provide a whole lot when he starts, and he's not really capable of going a full 90 minutes, only doing that three times over the last three seasons.
He's materially less effective when starting vs off the bench. Last season, two of his goals came from his 8 starts. The other three came from off the bench, where he got 5, 17, and 35 minutes in those matches. He recorded 0 assists last season.
Going back to 2018, he has an Avg Goals per 90 of 0.37 when he starts vs 0.72 off the bench.
None of the above addresses his much discussed defensive liabilities.
I like Jonathan Lewis. I would love to have him available off the bench as an option if we need to goal. Or even late to be a nuisance to the opponent when we're chasing a lead (can dump the ball deeper and have him chase). But he hasn't appeared to develop a whole lot. I don't think many disagree that he really didn't impress in the U-23 tournament either.
I don't think it's unreasonable to think, or really hope (as nearly all were saying above), that he turns into a more productive and/or useful player. Someone that can be reliable as a starter and is capable of putting in the defensive work on the wing, something that is incredibly important to Ronny's system.