Spoilers:
John Dee in the TV series actually is a more interesting character than the wasted-away Dr. Destiny from the comics. He isn’t just a one-note megalomaniac supervillain who wants to take over the world just because. He has reasons for what he’s doing.
A horrible, fucked-up, one-track obsession of a reason, but a reason nonetheless.
He’s sort of a less deliberately malicious TV Killgrave. Or Gollum.