I'd take issue with most of your observations. All 4 young players have improved. Hayward's shooting % decreased, but assists and rebounds were up. Favors has improved significantly in terms of his offense. Evans has a decent mid-range shot, although he's really not that big a part of the rotation, so insignificant.
I'm not putting "money" on Booker and Novak. I'm just pointing out that the difference between those two and Jefferson/Marvin is essentially zero - and maybe even an upgrade. And as for the PG situation, ANYTHING Exum contributes will be better than what Utah had for the first part of the season with Lucas/Tinsley.
Point is, Jazz didn't really lose anything important from last season (unless you're arguing addition by subtraction). Lindsey strengthened the bench. The team will actually be focused on defense and ball movement. No, this is NOT a 50-win team. They WON'T make the playoffs (although a Phoenix type effort might be a possibility). But 25 wins - i.e. NO improvement - is a ridiculous prediction.