Worst would probably be the mappacks that fail to run at all, with the infamous message "cannot find package....", atleast most of them got purged with the death of nalicity1.0
Anyway lets see so far:
dark2 -> modified dark arena.... infact the only thing modified was every texture changed into an xfx.utx texture
flotsam and jetsam -> an LSD trip gone bad
woopers maps -> almost anything by wooper, no reason to explain
CMS mappack -> not necessarely that the maps were that bad, but oh god... the music! (oh why use a cellphone RINGTONE tune as a music track?!?)