Matuidi follows the usual pattern since a few seasons:
1/ Very good 2-3 months at the start of the season.
2/ Average for 2-3 months.
3/ Usually good close to the end of the season.
Matuidi has many flaws, but he has qualities that made every coaches he had put him in the starting 11 in the end:
- Ancelotti once said "who the f*** is this player with no skill, he can't even control half of the balls". In the end, Matuidi worked hard, and gained Carlo's trust. He was a main part of Carlo's tactic.
- Same with Blanc.
- Same with Emery last year. And Emery doesn't want to sell him.
He has four qualities that Coaches like a lot despite all his other flaws:
1/ Lots of stamina. He's 30 but can run at full speed during 90m.
2/ Bulldog that gets lots of balls back.
3/ Can score goals, and his left foot is very good for that. Without him PSG would not even be in CL this season. Yup, he saved PSG's ass a lot for three seasons in a row now.
4/ Very good mentality. He's a winner. That's why Zlatan liked him a lot. he never gives up.
Given all that, you can understand why PSG fans are thorn in two right now: those that want to sell him, and those that want to keep him because his qualities are too good despite all his flaws (and Emery wants to keep him).
As for my personal opinion, Matuidi has limits he can't overcome. He's frustrating when he misses passes, and his ball control is questionable. That's why he can NOT be your midfield leader. He needs 1 or 2 very high skilled partners that can do what he can't.
I am not one of his best fan. But I always admit that whenever a big game comes around, he's always amongs the best, or at least amongs the ones that give it all.
But I am not a coach. All I can tell you is that all the coaches he had loved him as a player depsite his flaws. That includes Carlo Ancelotti who's not a beginner coach I believe.