Dredd's failure wasn't due to a bad movie, more to bad marketing and bad planning. I didn't realize it was running in theaters until it was already out of screening again. And judging from the comments above, I wasn't the only one. For the ones who still care: it is also mentioned in Bob's review of Resident Evil: Retribution. It came out at exactly the same time, and is the same sort of movie: Du,b action fun. But Dredd did a so much better job that it still holds up firmly in my top 3 of 2012. It also came out at the wrong point: it was September, which usually holds the movies that are not interesting enough for the summer blockbuster crowd, and people already spent their money on going to The Avengers and The Dark Knight Rises.
I distinctly remember a similar thing for another comic book movie: back in 2010 on a press conference for Iron Man 2, Kevin Feige confirmed that a Black Widow movie was in the works. It's three years later now and we haven't heard a peep from it since. Basically, this sort means nothing until we actually get an official confirmation that it will happen.
OT: So yeah, I'm pretty happy about this. But like you said, from ''Not off the agenda'' is a long way to ''Now that was an awesome sequel''.