Cena has not improved his wrestling skills in the slightest.
First of all, he has not even come close to putting a dent into his biggest weakness: his ability to SELL. He is still abysmal at selling an injury, and after every long and grueling PPV match that he has, he's jumping around the ring acting like an ass, flexing his muscles and pumping his fist as if he didn't just go through hell. For this reason alone, he is still one of the worst wrestlers currently gracing the ring.
But second of all, he has not updated his moveset at all. Head scissors as a rest hold? You think that is impressive? ALL OF US could do that. The guy threw one of his first dropkicks at NOC and everyone is going nuts. Don't you see how pathetic this guy is when it comes to wrestling? He can't even dropkick! And it looked horrible on top of that! An AA off the top rope isn't "expanding" your moveset, by the way. That's just a variation on the same thing he does over and over again (I understand it's his finisher and that he's supposed to do it repeatedly every match, but you cannot say that doing a very basic variation of your finisher is being innovative). And worst of all, he STILL delivers the worst, god awful, pathetic, disgusting, embarassing fisherman's suplex I have ever seen in the past two decades.
Cena has enthusiasm. He's a hard worker. He's a company man. He'll do anything Vince says. He's OK on the mic when he's not saying stupid things like "I'm happy for Randy" when Cena just lost a title match. Cena has many upsides as a superstar. But once he gets in the ring, he is a mediocre performer and I don't see how that won't always be his greatest weakness. Until he decides to actually TRAIN and LEARN new moves and better his ring skills, Cena will always be a lackluster star between the ropes, in my eyes.