what does sd-ext and 64/96 dataswap do and what audience is it ideally for? do you have to reinstall your apps after a flash of a different rom? btw, do you have problems with the launcher app drawer taking long to load? i tried both nova and apex, but both are plagued by the same problems. i tried the tweak to keep launcher in memory and it helped but i still have a slow down with initial opening the app drawer.
DataSwap compliments SD-Ext, with his rom if an sd-ext partition exists on the SD card it'll automatically move the content of /data/app and /data/app-private to /sd-ext/app and /sd-ext/app-private. Unlike most sd-ext apps it does not move the cache/dalvik-cache to the SD Card as that would only slow things down.
With DataSwap it places a swapfile on the /data partition (hence using the space freed up by sd-ext and splitting the usage between two devices rather than all on the /data partition), which is much faster than using swap on the SD card, although it will still use swap on the SD card if present, will just add it to the total swap (but will rarely be used as ~54MB seems to be the sweet spot with Eliterom). 96MB is used for people who tend to be heavy multi-taskers for extra smoothness.
I do not have a problem with the apex loader taking too long to load with at least the 64MB DataSwap mod applied, and the app list is quick in the drawer as well.
IF you switch to a different rom, then naturally you're going to want to wipe everything before flashing a brand new rom, as not wiping between different kernels/roms/systems is just asking for trouble (though upgrading to a new EliteMod Rom or Kernel usually does not require a wipe unless he specifies it in the change log).
PS: With sd-ext used, you
DO NOT move your apps to SD card, as /data/app* is mapped to /sd-ext/app* and you are already using that partition on the SD card for your non-system apps, moving to SD card will instead move it to the FAT32 portion of the card and performance would be noticeably degraded.
The G2/DZ isn't exactly ram friendly for ICS so swapping, whether it be with a mod like DataSwap or a swap partition on your SD card is advised for the best performance, otherwise you run into the sluggishness or forced closes you described when memory starts to cap out.