Matheson is just as good today as Petry was furing his good years for us. Offensively he is doing more or less the same work Petry was able to do. Petry was better at 3v3, but that's not that big of a deal.
Defensively Petry always had some issues, they are essentially at the same level where they play mostly good enough. Matheson is an even better skater and it helps him in all phases of play. Slightly worse offense and better skating allowing him to be more dynamic in zone exits. All in all, same role Petry could pkay and pretty much the same level of efficiency doing it.