Myself, and I'm pretty sure almost every Chelsea fan here, will disagree with that.
2014 Matic, I would stand by the claim that he was arguably the best DM in the world at the time. That mainly had to do with Mourinho's tactics, as he helped us absorb pressure and break on the counter. But since his injury in 2015, he hasn't been anywhere close to the player he once was other than the occasional good performance.
The 3-4-3 was a revelation to the Premier League, and teams didn't know how to set up against us. It was only against Spurs at the lane last season where we got truly exposed. You put pressure on our back 3 as well as our wing backs, we are screwed. We have vastly limited wing backs in Moses and Alonso, and Kante's on the ball ability as a midfielder isn't 'great' and Matic turns into a donkey in headlights under pressure. With all this set into place, we get over run in the middle. Don't take my word for it, look at teams setting up against us last season vs. this season. Last season, Matic literally took the ball, looked up and found a pass with relative ease. This season, teams such as Watford, Palace, Burnley, etc. They knew what to do against us and they knew our weakness and exposed it. You have to remember we had no European football last season, which played a HUGE factor.
CarefreeLuke will go bonkers when he reads your last sentence mate. . Matic was bar none terrible the 2nd half of last sesaon. The 2nd half of last season was where Kante got a bump on his statsitical numbers, because he was arguably doing the work of 2 midfielders. Matic was passive, lethargic, and slowed down the tempo of our play. He gave up possession so easily and his movement off the ball in defence was appalling. It was a point where his limitations of a footballer were exposed. So unbelievably inconsistent. Matic might look better now in a 3 man midfield now that he has to cover less ground, but it can't be ignored how utterly awful he was for us during that period of the season. You just have to look at Spurs in the FA Cup semi final and Arsenal in the Final to see my point. Nothing but a passenger.
The main difference what Bakayoko brings us, is his dynamism. His ability to run forward with the ball, which has worked well in our system. Despite his recent performances, he has done well in almost every big game this season, Atletico away, United at home, and last night against Arsenal were easily his best performances. I have patience with him due to his age, but I have no doubt in my mind he was a better long term solution and better fit for the system than Matic.