So what your trying to tell me is Eichel was a bad linemate when Reinhart was on RW with Eichel as his center.
In terms of what is best for Reinhart and his development as a player, yes Eichel was a bad linemate for Reinhart to play with. Playing with Eichel, Reinhart deferred to Jack more often than he should've, not to mention Jack away from the puck isn't the best support player. Playing with Jack hindered getting the most out of Reinhart. Plus, the coaches limited getting the most out of Sam because they viewed him as a playmaker from the RW, which is comical and hurt Sam's chances of getting the most out of him.
For Reinhart's development, he should've been put in position to be with players that can work give an go's to breakdown teams' structure. It's why his play with ROR, was levels above what he was doing with Jack.
Jack is more of a one man show that if he can control the pace, he just needs guys to work on getting the puck loose (a weakness in Reinhart's game), and to get open (Sam's mobility in his skating to do that is effective, but not a strength).