A sequel with the Dark Judges would have been epic as well, and it could have retained the dark claustrophobic feel of the first one. I loved Urban in the role.
It tanked in an almost unbelievable way in the US, so there wont be a sequel, annoyingly.
I worry a sequel is going to be more sprawling in plot and location as I think it would be worse for it. The tightness of this is what gives it tension and momentum. I'll be interested to see it though.
The general theory is the US dont know what Dredd is and thought it was a sequel to the stallone movie.