Henderson is often maligned by his own fans.
But Richards told BBC Sport: "Henderson, you'd argue Henderson's world-class, because of what he's done and consistency and whatnot.
“He's won a European Cup, he's been consistent over the last three or four years. Yeah, it really is [hard to write off a Champions League-winning captain].
“You know what, I'm going to go with that statement, I'm going to say Henderson is world-class and a lot of the work that he does goes unnoticed because he's not getting 10 assists a season or scoring 10 goals a season.
“I was referring to on the field but off the field as well.
“I've played with Henderson and he's just an honest guy who would run through brick walls for you, he's willing to improve, he wants the team to be at its best.
“When Liverpool first signed him a lot of people were raising their eyebrows but now I think we have to start giving him the credit that he's due.
“I watched him in the Liverpool-Man City game and he just doesn't stop running."