I don't know on the fence with this, and it seems you are also. Coop has limited Callahan's mins since he no longer is on the PK, so to get top line mins is likely Coops plan. When Stamkos is having a really good game we get those multi point games from him and Callahan and they click. I see a lot of good and potential but the line has not been 100 percent because of Stamkos' inconsistency this season. I feel the best option is to keep a top 6 forward on that line. Since flip is centering the 3rd that leaves Callahan . I also think killorn on there has fixed those getting pinned in the d zone moments. That line is a plus 3 since its been together for 3 games now and has scored 3 goals now as well.
Coop won't be Changing anything yet, that line scored and had good looks all night from all 3 players.
What it comes down to is Flip/Callahan > Stamkos/Callahan. Top 6 doesn't even really mean anything on a team that has Filppula centering its 3rd line.