Leier brings great energy in the O-zone, but if these guys aren't playing the scheme in the AHL, it takes time for them to get on the same page with the rest of the team. I think you'll see Hakstol gradually increase his ice time, I doubt he's going back, adds an explosive element to the bottom two lines, which sorely need it.
I think there's a simple reason Ghost doesn't play at the end of tight games, he gambles with passes (count on him for at least one "what the f--" pass per game) and he's too small to clear the crease.
On the other hand, MacDonald has trouble defending the blue line and is reluctant to engage in physical play - which is why I love Mr. Gudas, what he lacks in pure skill he makes up in nastiness and heart. You pay the tollkeeper when you bring the puck into the O-zone on his side of the ice.
Provorov is really getting aggressive on offense, guess he now has a feel for NHL speed and is more willing to gamble.
They looked pretty good the last two games, this evens out over a season, win some you should lose, lose some you should win, but play a lot of one goal games and eventually they'll go both ways. Top teams stay out of one goal games by burying the opposition on a regular basis. Flyers aren't there yet.