Correct me if I am wrong, but in Final Fantasy, at least from IV onward (so the 16-bit ones), there were save points in dungeons. And in Dragon Quest, if you died, you were sent back to the latest church you went to and lost all (or half?) of the money you were carrying with you (but keeping xp, items and the cash you had in the bank). Phantasy Star IV decides to go for worst of both worlds: there is no save point in dungeons and when you die it resets the game (it literally does: you get the Sega logo and all). It's ok in most places because dungeons are not very big, so, as mentioned before, exploring them thoroughly in several trips is no big deal, but then comes the Air Castle...
By the game's standards, the thing is giganormous and at some point you wonder if you want to push through or port out to save but have to redo the whole thing again (the Dark Soul design to have shortcuts get progressively unlocked is kinda present, but it splits the dungeon in two and the first part is super big on its own). I pushed through and survived, but I would have been supremely pissed if I died! Obviously this tension is lost when you play on emulator with save states and all, but I am not sure that's a very good tension to have in your game, especially when you consider we are not talking about a 5 min chunk of gameplay here, it's more like 30min, maybe even north of that.