First, Ronaldo is a quality player, but I think he's rated too highly from playing in a league where there are only 2 teams with MOST of the rest being average, and spanish so not the best defenders. For this reason I'm out.
Secondly, I'd take Hummels in summer but I think he may struggle to get into the stride of PL defending.
Thirdly, the one person i'd take no questions asked would have to be christian eriksen, looks quality and only 20 years old...
I'm quite surprised there hasn't been more on a second cm of yaya's quality mentioned half as much. A schweinsteiger/tiote/de rossi and maybe Gokhan Inler would serve city well. I think Inler is underrated and tiote is well proven and deserves a higher ranking club imo, but Roma & Bayern are highly unlikely to sell anyway.
Overall, Eriksen in January and possibly a right footed dribbler. HAzard? Lavezzi? Take your pick... Anyway, that's just what i think...