Although I haven't done any of these attunements since I only started playing end TBC/begin wotlk, I do remember some of the smaller "attunements" like class quests to unlock druid shapeshift forms and I believe a few dungeons where you required a key.
IMO attunements are great. They make the content feel worthwhile and make the journey feel like an adventure. Maybe some attunements were worse (specifically the ones that required you to grind a lot), but others like the SSC attunements seem proper.
Nowadays, especially later in the expansion, people just skip 90% of the max level content right into the current end content. Blizzards excuse was 'because people weren't seeing the end content'.
Sure, people can skip to end content immediately because of catch up gear, but meanwhile they're missing out on a ton of content because of it. Also, I don't consider LFR real content since it's a watered down raid experience.
Currently IMO the game just feels watered down. There's nothing exciting left to be done. The only content left is raiding and PvP. Which on themselves is OK, but not when you can literally hop into them on the day you hit 90.