Agree with most of your post,but I'd take a look at Vierra again. For me he has to be in any top premier League team.
Also u mentioned Yaya playing up front ....well he definitely played centre back for us( got sent off iirc ) and for Barcelona ,in a champions league final v utd marking wayne Rooney out the game.
Not something David Silva could ever do...
Yayas career dwarfs many players,in so many ways, Silva was utterly brilliant at his game,no doubt about it,but Yaya was a all round player,could put his foot thru the ball when shooting either foot,or could just delicately place a 25 yard shot in the top corner of the net in a blink of an eye.play a 70 yard pass to a team mates feet,could run at speed down the left wing (westham away ) through the middle of the park ( villa at home ) or down the right wing ..( Sunderland away )
Nobody could stop him......
People forget,just how great Yaya Toure was....in tandem with Silva,they broke so many opposing centre midfields to bits. Privileged to have watched that tbh.