Basically you seem to want to use "medieval fantasy" as a weird-ass
codeword for "less dimension travel, less talking to powerful beings, less magitech, and so on". And yeah Vanilla has less of that. But not a whole lot less. If TBC is like, an 8/10 on that scale (and it is, because it's pretty much 24/7 that stuff), then Vanilla is a 6/10, maybe even 6.5 (because we can't exclude AQ, Naxx, etc.), and then Wrath is like a 6/10, and Cata 9/10, WoD 9/10, MoP hard to rate, but I'd say 7/10, WoD is a 7/10 (apart from the dimension travel/AU aspect, it's pretty fucking grounded), Legion is a 10/10 peak over-the-top-ness, BfA is back down to a 9/10 and would have been like a 7/10 without 8.3/Corruption/N'Zoth, because despite all the HEAL HER WOONS, most of what's going on (i.e. the zones, war campaign, WQs, etc.) is the most grounded shit WoW has seen for a long time, in the actual zones and quests and so on. SL looks like it'll be 11/10 I admit, but I dunno, I like "otherworld"-type expansions in games in my experience.