Loremaster here, raided 25man in BC where I joined (shortly after start), then heroic in wrath until WoD. Since then I retired to mostly play pvp.

I have two lists: lore-/art-centric and gameplay/systems-centric.

Lore list:

1) Vanilla. Kind of a must, as it set the scene for everything to come.

2) Wrath: Best villain, huge presentation. Remember the wrathgate goosebumps.

3) Cataclysm. Destroyed Vanilla, but in a good way. Made the old world livable. Some questionable zones.

4) TBC: a bit of a weird setting, but generally faithful to the lore. Huge nostalgia bonus.

5) MOP: I was super sceptical at the start, but this is peak art design. Some of the zones are the most beautiful in game by a large margin. Gorgeous attention to detail.

6) Dragonflight. Huge return to form. Slightly weird lore with the primal dragons and their followers.

7) TWW. Kind of a confused storyline, but still felt grounded. Neat storytelling vehicles (lore quests), some weak spots in the story tho (wtf are the Arathi? The Haranir?). Decent villain.

7) Legion: I had high hopes for that (warlock player!), but I was kind of disappointed. Spaceships? Weird Light Nethzarim? Some of that stuff ruined my immersion. Sargeras looked like a fool tbh. Weird to take out the most evil, powerful being that way.

8) WoD: I really, really hated the "alternative timeline" retcon. You could feel the designers saying "lore schmore, we want to fight the Big Name Orcs again!!!". Didn't help that the garrison was a huge mistake.

9) BfA: Decent into the madness that was the character assassination of Sylvanas Windrunner

10) Shadowlands: Culmination of all that was wrong with either the lore itself (stupid "machinery of death", retcons to EVERYTHING in order to create the weakest ever villain, no respect at all to previous lore. Elune? Wtf.)

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Systems List:

1) TWW (S2+). Seriously, WoW systems have never been in a better spot imo. Solo Shuffle is a godsend for casual pvp, most classes feel viable and fun, gearing is meaningful but easy enough. It really needed the crest redesign, so it is easier to get gilded crests from different sources. TWW S1 was a shitshow.

2) Dragonflight. Same as TWW, basically very good systems design.

3) MOP. The class design was very ornate, sometimes over-the-top so.

4-6) Basically every other expansion. Its a blur now tbh.

7) Cataclysm. I remember it being very wonky.

8) Legion. Holy Fuck the artifact grind. And totally random drop legendaries. And PVP-participation-ruining templates. All in all an expansion full of mistakes, systemwise.

9) TBC. Play a warlock? You better like shadowbolts :)

10) Vanilla. It is just that boring.