Following my plan from yesterday, I stripped Aeth down to bare bones in order to see how close I could get to a character that might actually be challenged by Old World content. With no glyphs, no talents, no buffs, and no gear except a Simple Black Dress and Embroidered Boots...
... Aeth ended up just shy of 40k health and just over 20k mana.
The mana really isn't an issue; since spells cost a percentage of base mana now, the actual spell costs scale pretty well. In this configuration, she can manage a couple of Flamestrikes or just short of a dozen Fireballs before running OOM.
Damage seems to be... kind of OK. In a Redridge, she was still one-shotting most mobs with a single Ice Lance. Moving on to Searing Gorge, mobs were still taking 1-2 shots to down - not bad, but not quite the kind of fight I was looking for. If I could downrank spells, that would help, but unfortunately, downranking is a thing of the past. Oh well.
Health is the real issue. Aeth didn't even have 40k health, fully buffed, at the end of Wrath! So essentially, when doing Old World content, even stripped down, I'm still in god mode... incredibly hard to kill and doing a whole lot of damage, even without any buffs.
To make this work, I think I need the opposite of (the original) Martin Fury - I need a shirt made of nerf. I'm thinking of a BoA item that scales your health, mana, and stats by whatever percentage is needed to put you in the level mid-range for your current zone. Call it an "Ascetic's Hair Shirt", let me equip it to scale me to the right power level, and I'd be happy.
For the time being, though, it looks like "Operation: Ascetic" is a failure. Curse you, my expanded health pool!