I just watch them play when Lallana Coutinho and the tricky small black player (name obviously forgotten) are all out there healthy, and they outplay everyone in all areas of the field UNTIL a set piece comes along, and, if they're going to lose, that's where it happens.
I used to watch hockey a lot, but I think that it's a different situation --- a Crosby or a Hull or a Gretsky etc can often win with "just" well-organized effort-high teammates. It's tough to score in Hockey, but I believe that it's even tougher to score (in the run of play) in Soccer. And since Hockey doesn't have regular set-pieces moments where the thugness of the team would matter most, it's probably easier to survive without superior thugness in a lot of cases. All the major Soccer teams that I've watched several times, have serious "presence" around the box. Liverpool does not.
Defensively, it's certainly physicality when it comes to a "normal" service into the box --- heavy amounts of semi-subtle pushing/ blocking/ impeding/ holding there, plus the ability to get up and head it out of there. Offensively, you need a real jock --- someone who is quick and clever AND STRONG ENOUGH to swim move past the impeders and then go vertical with authority --- I marvel at how Ronaldo and Vidal can soar over some of those guys.
Anyway, my opinion. I instinctively like Klopp and so have grown to root for Liverpool when they play --- he seems to be a Man'sMan and a really good coach players-wise.
I also looked up Van Dijk back when he began to be mentioned on this thread, and said --- YES.