Think Henderson is one of those whose qualities goes under the radar, but he facilitates play in a big way and plays better than the sum of his parts. Rodgers came in and immediately wanted to sell him, he eventually went on to make him captain. Klopp came in and Henderson went up a level, and while he's lucky to play under a manager like Klopp, he does play an important role for them.
Mikel was a very consistent performer for Chelsea, and while I think Chelsea fans liked him I remember him being ridiculed by other supporters at times. Think he was liked by the managers he played under though. His calmness on the ball and metronomic passing were useful for various managers.
Giroud was often a pretty frustrating figure, but recently Wenger was talking about some intangible quality he bought and whenever he dropped him the team suffered. Played an important role for France under Deschamps too. Admittedly was often not a starter in the league for Chelsea but was getting on.
Kyle Walker moved for big money and has won a lot of plaudits, but I often see him being criticised online. Think he plays an important role for his managers though, domestically and for the international side. While employed in different roles, his recovery pace is very beneficial to the sides he plays for and can often facilitate playing quite high. In Europe last season he made some very important tackles/recoveries.
