I think it's really difficult to set the integration from U23 to first team at the right level as you either end up with:
a) Loads of deadwood that are too good for U23 but nowhere near first team
b) Overpowered youth players in your first team
At the moment, from my perspective, it is very heavily in favour of point a, in the fact that I put a lot of minutes into a few youths over the season and now they don't get a kick in the first team as they are too far adrift. I've become a bit distracted from actually spending time on my youths this year through one thing and another, and to be honest I probably wouldn't be sad to see them go personally. However, for those that do spend the time sheeting every round and nurturing their U23 teams properly, there should definitely be some reward.
Just an idea, but is it worth having the leagues restructured so that managers who want to sheet can be in one league, and the clubs who have a low or 0% sheeting rate this year are put in another division? Therefore you get the competition for those who want to invest their time in it, but also for those who just don't sheet it won't have an impact on the season? For example, I haven't sheeted much, but I did in a few odd games recently and it may have cost sides who expected us to play a default tactic? It's probably not the best approach, but just hanging ideas out there