Considering that he didn't have a proper pre-season with Chelsea last summer, due to his move to United, and that he didn't get any time to settle in the team but he started playing 90 minutes right from the start and with a makeshift defence behind him, he did just fine. I expect of him to do even better next season, now that he's adjusted to his new environment and with a full pre-season which is very important for a big guy like him.
I don't think many realise how important is what he actually brings to the table for us. The lack of a disciplined, cool-headed and positionally aware midfielder was one of the things that really plagued us since Carrick's form started dropping in the post-Ferguson era. I mention Carrick because even when he had the season of his life in 12/13, lots of people still wondered what he did well. I still see some of the same comments regarding Matic: "he slows us down", "he takes too many touches on the ball" etc. What about his role in our defensive transitions and the protection he provides in the central channels? Because that's what he's primarily here to offer. And it's no easy feat when for the most part of the season you play next to players who either don't care much about defending (Pogba) or lack positional awareness (Herrera).
As for getting the ball out of the back, it's one of our failings of the season that we wait from Matic to do that too. Absolutely ridiculous ball-carrying and passing skills from the FBs, all three (presumably) adventurous CBs on the ball out for huge chunks of the season for various reasons (Lindelof, Bailly, Rojo) and since Pogba firstly got injured and then decided that he doesn't want to play deeper, no creative options from deeper positions in the midfield. There are people responsible for this (not to be discussed on this thread though) but none of them is Matic.
Good signing overall, solid performer but not a game changer when we have the ball at our feet. Once (or if) we sort out our midfield, his contribution will be rated even higher from our fans.