Even that is too much to ask, and by doing so, he essentially gives his best part of his game, aka scoring a shitload of goals.
I think that Riquelme had a better understanding of the pitch, his passing was even better, he had more tactical discipline and at least he tried to defend (Messi doesn't). Messi of course is a way better dribbler, and that counts a lot for an attacking midfielder. Anyway, Messi can become a lite/worse version of Riquelme and sacrifice his almost unparalleled goalscoring abilities, but there is no point on doing so. He is at best as a 9.5, terrorizing defenses by scoring 40-50 goals per season (I don't think that he is able anymore to score 50+ goals per season, but no active player is), while also making 20+ assists per season and creating some good chances by dropping deep.