This is going pretty far afield of the topic, but at this point it seems fine:
Probably the biggest weakness of 5E is that it can't decide whether it is a Dungeon Fantasy game or not. Half od the design choices point toward dungeons, but the other half don't -- and the "culture" presented in the official modules certainly doesn't. You are absolutely right in your comment "needed a bigger dungeon" because the attrition of hit points and spells that "balances" fighters versus casters is built around the dungeon. The PCs should be pulling out when they are spent, hauling whatever treasure they can carry and considering knocking out the torchbearer's knee in order to slow those trogs down.
But not all of 5E embraces that. While we still have wizards and fighters, we also have warlocks and other "short rest" classes. We have too many resources that don't suffer attrition, and we have too many cheap or free abilities that bypass the difficulty in the dungeon and wilderness.
I think D&D needs to decide what it is and excise the mechanics that don't support that. The OSR showed that people do in fact still want resource management and dungeon procedures -- and not just us old farts. But not everyone wants that. The Hickman mode is alive and well today. "Stories" are something a lot of people want -- and not just the new kids. The thing is, D&D has never been good at doing them both well, and I think 5E is particularly bad at the former.
Maybe there is an answer that allows D&D to be both, but I don't think so. Frankly, there is probably more money in the latter, story oriented play, so they should kill those dungeon crawling sacred cows that exist only in diminished form anyway.