AWB was as consistent in his defending all season as TAA was in his attacking so he's hardly flavor of the month. I remember first hearing about AWB when he took TFM's spot on the Crystal Palace team while he (Mensah) was on loan there. He's been making a name for himself since
Man, the best fullbacks are either two-way or pretty good in attack, forget being a 'beast' defensively. TAA is one of the best fullbacks in attack out there and for that, he will always be rated ahead of AWB unless AWB somehow drastically improves his attacking game.
Kimmich, Robertson, Cancelo, Marcelo, Carvajal, Alba, Alaba are highly rated because of their attacking game moreso than their defensive game. Then there's the likes of Lahm, Cafu, Carlos, Evra, Alves. You rarely see anyone praising their defensive game moreso than their attacking game.
Attacking capabilities trumps everything provided the FB is no slouch at defending.