What I think is interesting is that we are seeing cycles of tactics and formations (that usually take about 5 years to go from one trend to the other) happen multiple times in this season or even in game as the top coaches have become so flexible and willing to do what it takes to win.
I remember when Hoddle really wanted to get a 3-5-2 going but couldn't, as firstly he didn't have the players fit but secondly Mourinho's 4-3-3 was about to come in. That version of the 4-3-3, with wingers pinning the full backs wide and a Makelele style holder creating passing triangles was best to beat the 4-4-2 and the 3-5-2. Then that 4-3-3 got phased out slightly with the rise of 4-2-3-1 and high pressing, and once most teams had switched to that, Conte and Poch (and to give them their due, Martinez with Wigan and Rodgers with Liverpool for a time), went to 3 at the back to counter act the pressing. An extra centre back meant that there was another option when being pressed high, while the 4-2-3-1 has a narrow 3 behind the striker that struggle for space.
Pep set up the team as a more modern version of the 4-3-3, with wide players pinning our wing backs and stretching our centre backs, and out numbering the centre backs when we tried to build from the back, with 5 players hunting down our 5. It's great that Poch changed it up. I'm not that scared that Pep will be way out in front next season. What he did wasn't that revolutionary, it was just the smart move. But just like Poch did, other managers will adapt next season and Pep's 4-3-3 won't be unbeatable.
If Chelsea win league this year, I think it's simply down to the fact that Conte went to his 3-4-3 before anyone else did. That gave him the slight advantage. Unlucky for us as I think we have the better squad, so certainly frustrating there. What we need to do (and what Poch has already moved us towards this season) next year is to be able to adapt to 3 at the back and 4 at the back systems and be able to switch fluidly in game, ideally without a sub required. Dier is the perfect player for us to make that happen. Just a shame Wanyama can't adapt to being a more attacking force if we need him to.