Mine has been very sluggish lately, and I'm totally stock. I did a FDR after ICS.
I'm not certain, but my sluggishness might have something to do with Opera browser or Swiftkey. I've had Opera browser since I did the FDR, and it has worked fine up until recently. I downloaded and installed Swiftkey recently but I have NEVER used it yet. The sluggishness seems to have started (or gotten worse/more noticeable) since then.
I also use Swype, so perhaps that's the culprit...or any other member of my app drawer.