1. False. It does. In Pep's system as a defender you have to understand positional play, be comfortable holding a high line, serve as auxiliary playmakers when midfielders are being sat on, and be great at defending moves that escape the first wave of pressure, on the counter and at set pieces.Pep's system doesn't require great defenders (Mascherano looked world class next to Pique for example), and they almost always have easy one touch options to pass to. Being able to pick a pass in that setup is not the same as being able to pick one under pressure. Plus Fernandinho is probably the best DM in the league which doesn't hurt.
Just use your eyes, Stones hardly ever attacks the aerial balls and in the rare occasions he's put under pressure he often fecks up on the ball.
And in terms of that 3rd goal, watch it back, Barkley doesn't want that ball at all, he's just making space for Stones to pop it long. Atrocious decision to pass to him. That's not to say Barkley isn't at fault too once he receives the ball of course, but it's still a colossal feck up from Stones.
2. My eyes function well, but when they fail I go to the stats which show Stones in the top 3 of aerial clearances at City. He's scored a few on the opposite side too.
3. Stones had a bad game, not disputing that. Using this game as a summary of Stones would be as silly as using the home game at Tottenham as a summary of Laporte, or the away game at Barcelona as a summary of Van Dijk, or...