He'd get in over Mikel. I don't think he's a better player than Matic but Matic hasn't been getting much of a look-in under Hiddink.
He'd definitely get into United's midfield. You're vastly overrating their players if you think he wouldn't, though Schneiderlin and Herrera are playing well as a pairing and it's strange LVG hasn't tried that one out more often.
Leicester may be put into the other section I suppose as 'maybes'.
He'd play for Spurs if Dembele was injured/out of form.
He'd play for City as they desperately need more energy in that midfield.
Arsenal fans would have him as their defensive midfielder.
Think you've got to compare like for like. He plays DM for us (whether that means pressing high or making tackles) whilst Barry plays midfield creator (supposedly but enough of that).
Therefore is he getting in ahead of Schneiderlin? No, Kante? No, Dier? toss up, Coquelin? toss up, Matic? No, Mikel? No (hugely underrated), Fernando? Yes, Lucas? Yes.
He'd get into a few of those sides but I think it shows the general dearth in quality in defensive mids in the prem. We can't find one for England, there aren't many good ones at all which is why Chelsea were so good last year and maybe Leicester are now. Most teams are just too open and that has applied to us as well for most of the season.
The days of Petit, Keane, Makelele, Mascherano, genuine world class holding mids seem to be over. Even Carsley would stand out now as a very good DM.