sl/sl wasn't invented/popular until halfway trough season 2 when people got BT SR gear to counter sp/warlock. all the locks played ua in season 1 to cover sp dots because that was the dominant comp. then warlock druid became a thing and sl/sl followed after that.
lol good thing you missed the bc boat and first half of wotlk. back then lock pets had a 15 MIN cd and an 8 sec cast time. getting pets back is so easy right now .... there are much bigger issues that need a fix. like our shitty fear and 1 school lockout. rogues could 1shot the pets with their silly +demon bonus on warglaives..