Guide: Best expansion to do dungeons in after pre-patch for Shadowlands
Sorry for the audio in pieces (I've since fixed the issue) TLDW At lvl 33 with rested exp
Classic - Stockades - 11.7k HP - 302 exp
Cataclysm - Blackrock Caversn - 7k HP - 264 exp
TBC - Ramparts - 5k-6.6k HP - 398-456 exp
TBC - Mana Tombs - 5k HP - 398 exp
WotLK - Halls of Lightning - 6.4-6.9k HP - 380 exp
MoP - Mogushan Vaults - 5.3k HP - 264 exp
WoD - Iron Docks - 8.2k-8.8k HP - 264 exp
Legion - Darkheart Thicket - 7k HP - 264 exp
With a final tally, Burning Crusade is by far your best option after the level squish, being both the highest exp per kill, and the lowest hp per mob. This also includes bosses which have a jarring difference in HP from 43k on some TBC bosses vs 70-80k+ on different expansions.