Jost will never be fast enough for some but he is fast enough for Jared Bednar to keep him at center for almost two months now, and his demands on skating are much higher than anyone else here.
He's been working hard, generating chances, and playing good defensive hockey since he was called back up in February. All he needs is a little more ice time and some consistent decent line mates. Even his five game point streak, and his three game point streak to end the season, he still only got 9-12 minutes of ice time.
Trying to judge his peak ability with this little ice, and some combination of Bourque, Calvert, Wilson, and Andrighetto isn't going to give you an accurate read. Put him back with Landy, or put a Ferland type on his wing, and you'll see a lot more sustained O zone time and more scoring chances.