Classic Low level dungeons are too easy

Haven't played WoW in years other than returning for classic, and my first dungeon in (on my level 50) I saw that casters in particular never go below 95% mana. Why are the mana pools so unequal to their cost? I get people want to level through stuff quickly but I'd rather have more challenging content that rewards you with higher XP gains than a boring, long face roll all the way to 120...Also, does anyone know what level dungeons get "hard"? (As in actually having to watch what you pull and watching mana pools, super basic stuff like that.) via /r/wow https://ift.tt/3codJtA