Not too long ago, Volition announced that their DLC "Enter the Dominatrix" was going to be the foundation of the next game since it was too expansive to just be another DLC package... or whatever... so it makes sense that they used the same assets from the Third and went from there.
As for the content itself, I could go either way. I enjoyed the Third for the fact that it realized it was a game and pretty much just told the player "go have fun." Some will lament the fact that it's no longer just about taking over gangs (unless its now alien gangs and also, I would assume, politcal powers), and that it has gone too far off the original premise, so on. Fair enough, but at the same time, it's also interesting to see a series continuing to try to go to the next level of ludicrousness.
The Saints series is one of the few series that I can replay over and again. I'll be keeping tabs on this. Thanks for posting.