I disagree. It's the Juve model, which was classed as a top 2 midfield at the time. Pogba and Pirlo lacked energy, so Vidal worked really hard and was class on both sides of the ball. Pirlo although slow, defended through his positioning and distributed the ball with his class. Pogba provided that extra magic by dribbling at defenders, giving the killer pass or scoring a crazy goal. All 3 complimented one another and the midfield as a whole lacked nothing.
That isn't the only way to accomplish this btw, nor am I suggesting it is. Barca's midfield consisted of Xavi, Iniesta, and Busquets. Xavi was the constant passer, who is more mobile than Pirlo, but wasn't as good at positioning defensively. Busquets, nor Iniesta are as energetic as Vidal, but they don't have to be because there aren't two slow midfielders in Pirlo and Pogba. Iniesta is always buzzing around towards the ball or linking up with multiple players. Busquets is more mobile than Pirlo was, but was much better at breaking up plays, and didn't spray passes all over, but quickly supplied his teammates with his brain.
Similarly, if we had a more mobile DM like Garner, we wouldn't need some Vidal type midfielder to provide energy. We could do with a Modric type. There are multiple ways of achieving a complete midfield. I would prefer not having that Vidal type, though others might disagree. The reason why Vidal was needed and why Herrera/McTominay are needed is because the respective sides needed to cover for 2 slow midfielders.
Once the midfield is complete, you can emphasize possession, or defensive solidity, or go with extra work horses. Real Madrid's midfield had Kroos, Modric, and Casemiro. There are no slow midfielders really, but a lot of great possession type midfielders. It doesn't lack for anything really unless you value physical dominance.