Now bring it back! It isn't nearly as hard as it once was. I remember virtually invincible 1st level rats. I had to spend everything consumable on my way back in that run - fire potions turned out very useful as HP numbers weren't scaled then. Now you just hit the enemies and they just die, very simple.
With the old mechanics I had so many runs that I was confident about ascending and would get obliterated by floor 1-4 mobs. I had to play assassin and let the attack charge for 10 turns for each individual mob lol
I had two runs with that mechanic, first huntress, then mage. At first I didn't know how the now challenging ascension would play out, but I was pretty confident - after all, can there be any threat for one who's reached the amulet? I turned out to be so wrong then. I made it through in both cases, but I was close to death so many times. A wand of blast wave let me kill enemies instantly in some cases in the first run; I finished with a drained +6 staff of blast wave in the second one (also with other guaranteed environmental damage wands).