Has anyone actually gotten a “plain” damage setup to work in very high levels? I haven’t gotten close to that point, but almost every setup I’ve seen going into realm 50-500 or so is using ailments, percentage damage, or abusing abilities like the Mouth of Hell’s. I think someone was using a splash + super-buffed Brim Smith build to oneshot encounters, but even that apparently fell off. Naturally, as you go more and more over your level, the Attack stat falls off as enemies quickly get maximum damage reduction, and I imagine attack-based setups do fine if both parties were level 20,000; but when your party is level 1000 and the enemy is level 30000 you pretty much have to use percentage damage.
Though, if you are farming experience or resources, I imagine attack builds are the best since they’re the fastest (rather than waiting on percentage damage, poison, burn, etc, you attack and kill, even oneshotting parties with splash), I know one person made a graph explaining that Attack was best at first, then debuffs/ailments/% damage accelerates. I guess one problem is the only way to buff attack-power based setups in order to go that far out of your depth would require doing something rather silly that would be incredibly broken at lower levels. I imagine % based buffs don’t fall off as hard, though, as they increase your power exponentially; a green Carver (whose name I forgot) has 57 times more attack after ten party deaths, along with ten free attacks; if you have a consistent method of revival, you could eventually scale up no matter how far you go. Similarly, spamming Mass Bloodlust is helpful if you have some sort of prevention from being one-shotted like the Life Mage talent, as you’ll quickly reduce the enemy’s defense to manageable levels while increasing your own offense; and if you’re that far past your level, you’re going to die on hit anyway - it’s how I already fight Nethers in sigils at a low level; they do capped damage almost exclusively, so bloodlust helps buff my damage dealer and let them do more than minimum damage.
Edit: By “minimum damage/maximum damage reduction”, I mean when an enemy’s Defense reduces your damage as far as it will go; which generally happens quite fast once the enemy’s defense outstrips you - without buffs even my brim smith hits sigil Nethers like a wet noodle, but after one defense reduction/attack buff they start hitting 5-10 times harder.