My thoughts
4. 15 recent apps instead of just 8 <- 15 is a tad too much, 8 is fine for me, but another row of 4 would be pushing it for me.
5. Long press back arrow to kill app that is in foreground.
Bug 238 – Long press back button to kill foreground process
7. Ability to change system components colors without rebooting
8. GUI for scriptybox
Bug 252 – GUI for Scriptybox <-Yes, I loved Pete's BBToolKit when I was on Bugless
11. Desire HD "Hibernate"
Twitter / cyanogen: Yeah, CM6 "does" too
ht ... <- IDK, most of the time I reboot, it needs a reboot.

13. Tighter integration of ADW (in CM ADW settings is even in the main settings like GEM settings) <- only if it doesn't get in the way of launcherpro
16. Ability to pick what rotations you wish to allow or disallow <- Yes
Now as for:
3. Use scriptybox to update system apps like ADW, cytown, gmail, etc.
I noticed something kinda cool the other day, and was hoping this magic could be harnessed. I performed a clean wipe last week, after all the search and gmail updates were out. I then installed everything at 1 time via clockworkmod. On first boot, I hit the 4 corners to bypass the intro. Now I don't remember if i signed into gmail at this point, but the market was launched in a "update mode" without me telling it to. It updated the new gmail and search apps without an issue (failing only on Superuser). My guess is that this initial update is launched by the system and not user (thus higher privilages). If a call to invoke the phone to hit the market and update/download/install on its own like on first boot, that would be epic.
Additional toy: Adding Silent and Vibrate to volume control buttons like UltimateDroid (when pressing Vol+ Vol- keys)
Fix: Lock screen play button control launching & playing stock music program when pandora or other streamer is paused.