Since its pretty well established people don't agree with the OP i'll tackle something else.
I contest this opinion strongly.
Wotlk only looks good in retrospect, particularly to those who started then (which was a huge majority of the playerbase). On the surface it seems like it was perfect but it started the playerbases unstoppable descent into mediocrity. Dungeons were aoe spamfests where most classes just walked around hammering their 1 aoe spell the whole time. The entire first raid tier was cleared within days of people reaching level 80 and over 90% of it was recycled from vanilla Naxx except this time it was a joke. Later it also introduced the dungeon finder, the single worst addition for the community ever. It elevated being able to play badly into letting people play not only play badly but behave like dickheads without any consequences as well. This all combined together and climaxed with creating the incessantly whiny subsection of the playerbase that infest the forums/twitter now (I've paid my x per month too, i deserve EVERYTHING!!!) People coined the term "Wrath baby" for the newer playerbase back then for a reason.
Yes it had upsides. Ulduar was incredible (though it was cut short by the worst tier of all time...) and pvp was probably the best its ever been but the expansion was certainly not the hail mary posts like this suggest.