In attacking sense (even if Vidal was more deadly) yes, but in defense sense? HUGE HUGE gulf of difference, and the impact it had. Lead by example and set the tempo (as is the way Pirlo lead and made everyone take a breather by taking reigns at any given situation), bullied anything in sight. Pretty much Conte style, made sure everyone just gunho pressed the opposition machine like, dont let them breath.
Dont see that as much now, we drop deeper and are organised, move smart as a unit, Allegri prefers that, more guarded approach with slower tempo over frenzied hounding (but also not his fault Vidal is sold and you get no one that can offer same type of work in midfield, ala Allan or Naingolan etc), cant escape that, we simply lack the aggression and ability to hound and scare ball holders. I mean the best at it for us right now is our box striker Mandzukic, thats not a good sign. Vidal did the work of two players in such a style. Never underestimate that. The ability to be first on lose balls and give minimum amount of seconds on the ball unharassed for your average opposition player.
I will stop rambling and offer a visual aid for this very very important aspect we miss dearly, this a clip of Hernanes facing us from that season:
What do you notice?
look at $#@!ing Vidal, ANIMAL, but also look at all of the players, they were INSTILLED to be terriers in a way we lack now sadly defensively. This aspect is needed much more for CL big games too, and level of quality difference someone like Vidal brings, even he was limping he did more then Khedira is doing in this aspect right now.