Grays_1890
Barry Daines
I disagree with you here slightly... In the 4-2-3-1 it was typically the CBs who would fill in at fullback with the deep midfielder filling in as a central defender if a ball was played over the top into the channel by the opposition. That is why Pochettino liked having centre backs who had also played as fullbacks in their career (he spoke about this in a few interviews) as he needed his CBs to be able to be comfortable defending one on one in wide areas against the opposition's wide forwards.
Many a game, Dembele would do the shielding back in his own box down the channels, he was absolutely incredible at it as was Wanyama.
We don't have that anymore
We have a real lack of fluidity in this side, its very robotic