Currently (on my dev machine), it takes 0.690 real seconds just to parse and load dependent modules from ljlib.pl. (this is after warming caches unti the number stabilizes)
I experimented with trimming ljlib.pl, removing non-core libraries:
Start:
real 0m0.690s
remove ljcom modules: geo::ip, cracklib, inline
real 0m0.652s
remove ljlib.pl modules: ljlang, poll, feed, links, cleanhtml, htmlcontrols
real 0m0.588s
remove mail stuff from ljlib: MIME::Lite and Text::Wrap
real 0m0.547s
remove phonepost (and thus Blob) from ljlib:
real 0m0.512s
remove paylib from ljcom:
real 0m0.329s
And this is all without moving any functions out of ljlib.pl. For instance, LJ::send_mail() could move to a new LJ::Mail package, and that package could also require Mime::Lite and Text::Wrap.
We did this a while back, but it's time to trim it all again. (scary, though)