It's a good question.
Over the last ten years we've had a number of 'villains' (both long and short term) but here are some most notable ones;
- Phil Mitchell
- Janine (although she's become far more three-dimensional in the last couple of years)
- Chrissie Watts
- Andy Hunter
- Danny Moon
- Johnny Allen
- Jack Dalton
- Michael Moon
- Mad May
- Archie Mitchell
A general list.
Phil, in the last ten years or so has; taken a child away from its mother, amongst beating people up and generally being a bully, from his godson Jamie, his son Ben to even his own mother and has also covered up murder.
Janine has scammed several men, tried to kill her husband Ryan, and kidnapped a baby as well as stabbing herself to frame Stacey amongst other things.
Chrissie Watts, along with her then husband Den conned Sam Mitchell into giving over the Vic, and killed her husband, manipulating Zoe and Sam in the aftermath and cover-up.
Andy Hunter was involved in dealings with Johnny Allen, including an attempt to con him which led to his death.
Danny Moon was a Johnny Allen puppet, who killed Dennis Rickman.
Johnny Allen had a backstory as a notorious EastEnd gangster (a real one, not one the Derek dreams of up in his head) he was responsible for the deaths of Andy Hunter and Dennis Rickman.
Jack Dalton was head of the Firm - he ordered to deaths of several people - Den Watts, Kate Morton and Dennis Rickman.
Michael Moon slept with his cousin's wife, stalked Ronnie and set her up, tried to get his brother killed as revenge from his late mother's death, and conned Jean Slater.
Archie Mitchell was a rapist, a paedophile, a cheater, and a manipulator. That's pretty much all that needs to really be said.
Mad May, tried to force a caesarean on Dawn, and kidnap her child.
Against all of those villains, Derek fails miserably.
Derek, in his time has been involved an in dodgy booze deal, where Alfie Moon and Billy outsmarted him. He taunted an old woman on her death bed, bullied Lucy and Anthony Moon, and tried to manipulate Roxy and Billy Mitchell. He beat up MM. That's lame in comparison to all these other villains.