Maybe not how to coach in terms of play calling but I think it's the managements job to tell Joerger how to manage his players development because they know what they are trying to build. I think there needs to be a straight line of communication from office to bench so everyone knows what the bigger goal is and that no time or asset is wasted. If that's means telling a coach to feature certain players whether for trade, development, etc. I find no issue with that since it's the GM and the coach that should be side by side in all aspects of team building.
Communication is the key to any successful relationship.
Vlade should not ever tell coach how to coach, but he should let him know what his intent is with the roster going forward.
If Vlade tells coach Joeger, look, my intent is to build the roster around WCS, Skal, Buddy and Malichi going forward and I am not sure which veterans will be back next year. Then, coach being smart and doing what is best for him and the team, should cater his coaching and rotation in maximizing his chances for success long term.
In short, he should be using the remaining games as an extended training camp. He should experiment with different lineups and see which group of players, particularly which young players work best together and help them build chemistry together, while working in the veterans.
I think he has already started some of the chemistry building by starting WCS and Buddy. I think eventually, he will work Skal into the starting lineup, before the season is over.