Not really. Apart from the Dortmund game, they've been pretty awful, and no they haven't suddenly turned bad since Kane (4 goals in 5 games since he returned) returned, as much as Korean netizens want to believe. Against Newcastle they couldn't do sh*t and Son's "goal" was was basically an own goal. Their issue is that with their style of play their wing backs have 150% of what normal wing backs are expected to do, i.e. play as wingers to allow Spurs to overload the attack with 'wingers' being able to have that freedom around the box and defending at the same time. Given that now their CMs are not as solid as before, the defence is no longer better protected, so they are always going to struggle, and the Spurs attacking players have to realise this and stop hanging around the box hoping they can get the service as they used to.
I disagree that their CMs have been poor (well, maybe Wanyama). To me the problem has been their wing backs, whose importance you've pointed out. Rose, Trippier, and especially Walker-Peters have all been in bad form, failing to provide good service and link up with the attacking line, and certainly getting caught out of position (look at Rose today).
Well, Sissoko's been over played with Wanyama and Dier dealing with injury so he was bound to have an 'off' stretch. But clearly the main issue with Spurs decline has been the poor play from their FB/WB's. They get far up their flanks but provide no end product. Runs by Sonny and now Kane are wasted with no service. Then by Poch wanting to play this way it adds pressure on your CB's and forces Eriksen to play deep to help out the Centre Halfs and Winks and Sissoko. Rose has been poor, never know what the hell you're gonna get from Aurier and Tripps is good for set piece or two bur useless defensively. Vertonghen can't be your best WB. Add, Good Hugo and Calamity Hugo to the mix and it's no wonder bottom table teams try to weather the storm from Spurs and try to nail them on the counter. Everyone is doing it now.
Van Dijk played the 2v1 counter with Son and Sissoko perfectly. He realizes Son is the real threat there and lets Sissoko run in on goal while still forcing him to shoot with his weaker left. He's been amazing all season and pretty much the single biggest reason for Liverpool's success. Wouldn't be surprised if he wins the PL POTY.
they'll do what they always do...tease the fans with roaring finish. causing "Irrational Exuberance" among their fans for the 19/20 season.
The only other players I can think of who almost looked like they preferred their weaker foot are Eto and Cazorla.