The way I understand it (just an MEP PPL) modern carriers automatically send back to base even the slightest deviations of optimal speeds etc caused by hand flying the latest slippery machines such as the Airbus 320 family.
Such deviations result in a gentle call from the Ops to the PF recommending AP usage or just gently cautioning.
If this is true, such a nudge will stop people hand flying, it breeds a culture of "keeping your head down". In this case doing nothing improves your career development.
The end result will be that once someone becomes Captain, he will have hand flown just a fraction of what a new captain would have flown 20 years ago (and yes, I do accept modern airlines now contain a lot of safety features that work most of the time).
If then flying something like a Seneca, just for fun, is discouraged by company policies, there is no way for such young pilots to gain hand flying experience.
Perhaps all new FO's should be obliged to do a minimum of 500 hours of instruction at a glider or GA club in their spare time before becoming eligible for Captain promotion?