What I really, really like about SL is the zone variety. I don’t feel like the last expansions have been as… varied as SL is when it comes to zone aesthetics and design. The artists really knocked it out of the park.
I also really like how SL genuinely feels alien — it doesn’t feel like any Azeroth-based expansions (vanilla, WotLK, Cata, MoP, Legion, and BFA), and it doesn’t feel like any Draenor-based expansions (BC and WoD). It feels alien and different. (As it should! It’s literally the afterlife of the WoW universe.)
I also enjoyed all the secrets hidden away in this expansion — all those “tricky” mounts, pets, and toys.
And Torghast! Love that place… I only wish it was released in its 9.2.5 state.
And this one last thing — I acknowledge that people are gonna find this weird, but I actually like how the Blizzard devs went out on a limb to try new things. BFA felt like Legion, and Legion had traces and echoes of WoD.
But SL didn’t really feel like BFA and Legion — at least, not as much. It definitely felt like they were trying new things. Some worked out, and some didn’t work out.
So yeah, I liked SL. It’s not my favorite, but it’s solidly in the middle. The only downsides I’d say SL has are the class design and the absurdly long grinds.