For all of Klopp's positives - building a team and playing good football - imo his one big weakness is that he struggles to make subs that would benefit the team when he gets the starting XI wrong.
Liverpool were destroying Barca for the first 20 minutes of the second half, but they clearly needed better service and better finishers. They have Firmino on the bench, and TAA to play RB, and he does nothing.
It was a common theme in the City match earlier this year too - he started with Gomez as RB and nullified their right side as a result. For someone who's got a fantastic pass and cross on him, I have no idea why Klopp elects to play Gomez at RB instead of him, especially when he's up against Coutinho and not Messi.