Killed = Bionic
Phone graveyard = D1
Resting = Dx
Mine did the same thing, got really slow even a full wipe factory didn't help much. I looked at both the note 2 and DNA and landed up getting the DNA and I have to say it's night and day to the bionic. The 1080p screen is amazing, it fits in my hand whereas the note doesn't, the battery is twice as good as the bionic and its really thin. I'm a memory freak and the bionic with ics had like around 30mb free most times and with the DNA its nice to see over a gb free most times.
This is currently on the Reddit front page. Claims to fix 90% of all Android lags:
Source: [APK] Seeder entropy generator to provide significant lag reduction - xda-developers
Reddit: Fix '90%' of lags in android (Needs Root) : Android
Need to be rooted. I installed the apk on my Bionic, and I have to say it looks like it does make a big difference, especially returning to the home screen after running an app. Give it a shot.
I saw that my Bionic was getting slow after having loaded a large number of pictures on my MicroSD. Not saying that's your problem, but maybe the Bionic's not good with large numbers of files (temp or permanent).