These midfielders are not good enough, enough here being defined as being at the level of a top 5 or even a top 7-8 team. Some of Frank's eccentricities bring out the worst in them; but he hasn't turned a bunch of peak Dembeles and Modrics into players who do these:
You saw at the weekend how a 33 year old Xhaka was busting a gut to find himself openings right? Now look at the sharp contrast between that and this
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What happened there?
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Yeah I know, Bentancur in the second screenshot is looking at the opposite direction of Bergvall's ; just pointing out the passing opportunity that he missed by not scanning his environment properly.
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The same as above, although in this instance Frank's preference for direct play might also be coming into the picture considering how decisive and purposeful Palhinha appears to be with that long ball
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Can't shake off a defender, has to go back. If you think I'm being unreasonable by expecting him [and midfielders in general] to do better in such situations, see the next gif.
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See, it's not that difficult
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So, to recap, midfielders ;
are not totally immune to butchering even the simplest of passes
are often showing little enthusiasm for making themselves available when defenders are searching for a forward pass in vain
very rarely manage to escape pressure through dribbling
sometimes fail to spot, let alone actually make, those aforementioned simple passes
I could go on with even more footage; but don't see the point of boring you even more than I probably already have. You could try watching the next game of someone like Wharton, just an example whose game I'm more familiar with, to see yourself the magnitude of the contrast between proper midfield play and the stuff above.