Correct. Wipe always user data. /system will be formatted every single time you flash unless a package is explicitly labeled a patch.
[...]
Wipe has always referred to *user* data. When you're flashing a ROM, every partition other than /data and /sdcard is fair game. No ROM should ever touch the two of those. As for /system, /cache, boot, etc, never assume they will persist when you flash anything.
today i learned. thanks! phenomenal rom, by the way. an hour after flashing 3.5.1b1 and i'm back to running as i was earlier this morning.
[edit]
so i've noticed that widgetlocker has some irregularities when applied over face unlock. if i wake my phone (power button, natch) it immediately jumps to face unlock, then widgetlocker appears and expects input, and after that the fallback pattern-unlock appears. vinq 3.5.0/3.0.0 didn't do this... peculiar...
well, now it's just all weird. widgetlocker pops up first (now) and after unlocking wl the face unlock black-box appears, but the front camera doesn't activate, but it DOES accept my pattern unlock (drawn blindly on the face unlock pane.) it's like face unlock has higher priority over widgetlocker and tries to execute first.
ima play around and see if i can't find something worthwhile in logcat.
[further edits]
yeah, face unlock combined with widgetlocker seems completely borked in 3.5.1b1. can't find anything interesting in logcat except for the fact that anything mentioning facelock isn't called whatsoever within waking the screen, swiping past widgetlocker and authenticating past keyguard/pattern/screen lock (input pattern on face-unlock "black box.") curious, indeed.