The traits of the Legion Weapons had major damage effects. Especially the 3 gold traits, which in some scenarios contributed like 30% of your damage each (e.g. the execute damage in the affliction artifact in m+ aoe). You also not only had to grind AP, but also Artifact knowledge (which increased your AP gain) each week, which meant you needed to farm order ressources each week. Ontop of that you needed to grind each of your specs individually, meaning Legion was not only extremely alt-unfriendly but also offspec-unfriendly on levels previously only seen in classic.
That's a matter of taste. But in SL you could just ignore the anima grind, which only meant you were at most 1 week behind in your covenant progress. You also could entirely ignore the Maw grind. And there were no dungeons locked behind main campaign progress like there were in BfA and Legion.BfA was absolutely a grindier expansion than SL - but SL was just worse to play by all accounts. At least people enjoyed BfA's zones. The only zone people generally enjoyed in SL was Ardenweald, only because it was pretty. Genuinely, going to any of the SL zones gave me splitting headaches because of how badly I hated every one.
Again, probably a matter of taste. I quit Legion early on, because I could not stand having to play the game with skeleton specs (WL was gutted going into Legion). Every major ability trait was locked behind a grind. Not fun at all. BfA was slightly better in that regard, but Island expeditions spam was just... bad. So I liked SL the most. Because I actually liked Torghast most of the time. And I just ignored the maw. Anima I got running m+ and only used it on the weekly quest. So aside from Torghast SL had no grind for me.If the grind is more intolerable, then imho, it's grindier by that account because the 'grind' suggests work you typically don't want to do but must in order to progress. I wanted to do SL's grind much, much, much less than BfA's, and that's saying something. BfA's was a gargantuan waste of time. There were enough positives in that expansion to at least keep my attention slightly more than SL, though.
I grinded Korthia rep for the crafters mark recipe to make millions of gold early on in the patch, but that was it.