They are? What functions rely on the BSAs being loaded? Does it matter that I only use it with Oblivion since I don't play much FO3, let alone mod it?
As far as I've seen, the scanning of .BSA's is only useful for TES4Edit (Set all REFR with VWD mesh in this file/as override into...) I could be wrong, but I've never noticed anything ...off with my game or FO3Edit over skipping the archives for Fallout 3 entirely.
Personally, I don't use .BSA's for the sake of reducing the editors' loading times (shaves at least a minute off each FO3Edit/TES4Edit load), not to mention having everything unpacked facilitates PyFFI'ing/tinkering with assets.
Here's what I do for my Gamebryo installs to pull out the archives/satisfy ID:
1) Make a ;Data directory
2) Extract all .BSA's to ;Data
3) Rename Data to ;Data/Merge normal directory over temp directory to ensure modded assets overwrite vanilla ones
4) Rename ;Data to Data
5) Comment out
*sArchiveList and SMaster*ArchiveFileName entries from .INI (GECK/CS .INI's too)
6) Set
*bUseArchives to 0 in .INI's
7) Save .BSA's elseweyr (external or whatever) as backups, just in case.
8) Done. FO3Edit/TES4Edit skips the archive opening every load thereafter ("[00:15] Background Loader: finished"). Game/editor runs identically.
* Spoiler [Archive]
;SMasterMiscArchiveFileName=Fallout - Misc.bsa
;SMasterVoicesArchiveFileName1=Fallout - Voices.bsa
;SMasterVoicesArchiveFileName2=Fallout - MenuVoices.bsa
;SMasterSoundsArchiveFileName=Fallout - Sound.bsa
;SMasterTexturesArchiveFileName1=Fallout - Textures.bsa
;SMasterMeshesArchiveFileName=Fallout - Meshes.bsa
;SInvalidationFile=ArchiveInvalidation.txt
iRetainFilenameOffsetTable=1
iRetainFilenameStringTable=1
iRetainDirectoryStringTable=1
bCheckRuntimeCollisions=0
bInvalidateOlderFiles=1
bUseArchives=0
;SArchiveList=AII.bsa, Fallout - Textures.bsa, Fallout - Meshes.bsa, Fallout - Voices.bsa, Fallout - Sound.bsa, Fallout - MenuVoices.bsa, Fallout - Misc.bsa
Some might not want to go without archives, but I don't miss 'em at all. The unarchived install size is substantially larger than that of a default one, but potentially worth it for those who open FO3Edit/TES4Edit frequently as those minutes add up quickly.