Sir Thomas More: No, I've neither read nor seen it. I did see A Man for all Seasons, of course, on the hagiographic side; on the critical side, Margaret George's novel about Henry VIII. has a go at him not for the killed heretics (since the novel is in Henry's pov, that would have been tricky to pull off, considering Henry was still going after heretics after both Thomas', More and Cromwell, were dead), but for the hairshirt and the self flaggelation, which reliably seem to freak modern readers out and which George's Henry is appalled by as well.

re: Jeremy Northam's More - I think for a mixture of both generally sympathetic but also fiercely intolerant re: heresy, but yes, not particularly (intentionally) witty. Then again, neither are the other characters. Now Robert Bolt's script completely edited out the intolerance and the going after heretics, but he had the celebrated playwright advantage with the dialogue, not just for More himself but also the other characters. I mean:


King Henry VIII: Thomas. I chose the right man for chancellor!
Sir Thomas More: I should in fairness add that my taste in music is reputedly deplorable.
King Henry VIII: Your taste in music is excellent. It exactly coincides with my own!