Messi didnt spent most of his career objecting to being used in roles that removed him from having those responsibilities.
Gerrard was a wonderful footballer, but in terms how he fit into the tactically evolved game that existed by the time he was on the scene he had limitations. None of them were technical limitations or related to his ability, but mostly his vision for what he thought he should be responsible for doing. It was a English disease of the time of wanting to be allowed to be Bryan Robson despite that role being 20 years out of date.
I think that criticism of him is often overdone and so many will take issue with my rendition of that, but it is an example of how it complicates his legacy (actually, maybe legacy isnt the right word because his legacy IS istanbul, the 06 cup final, all the other goals) beyond a basic judgement of how wonderful an overall footballer he was.