Quote Originally Posted by PairO'Dice Lost View Post
It's not impossible with practical optimization at the 6-8 level range, before even getting into TO territory; the fact that it is in fact possible means "It can solo the tarrasque!!" isn't a good measure of power or lack thereof. 20th-level characters are nigh-unto gods; the problem isn't with the PC's power level, it's that a puzzle monster with no ranged attacks, no magic, and no countermeasures aside from bouncing rays isn't anywhere near CR 20.
Could you tell me what that build is? Last I saw it takes more like a cleric 13, or several dozen of archers. And again, the monk is standing there trading blows, not flying safely out of reach: if you feel in a direct brawl, trading attacks back and forth, the tarrasque is underpowered for CR 20, then you have really different expectations of what is appropriate for martial characters.

Quote Originally Posted by PairO'Dice Lost View Post
DR 20 is not nearly as amazing as you seem to think. Heck, a vanilla rogue 20 with the TWF tree and appropriate WBL is getting at minimum 16 damage with sneak attacks, and after other typical feats and items should be hitting a minimum of 25 or 30 damage per attack for 6-7 attacks--and rogues aren't even primary martial damage-dealers.
Please, run some math for me. Calculate how much damage that rouge does, assuming he gets sneak attacks in this 1 on 1 battle, on average, both with and without that DR/20, recalling that the monk has 41 AC. Calculate how much damage the monk does.
Here, my numbers are:
Rogue: ~14d6 + 8 damage, at +33/+28/+23 to hit, twice. Average damage against 41 AC, about 150 per round. With 20 subtracted from each hit, that drops to 100 per round.
Monk: 6d6 + 24 damage, at +39/+39/+39/+34/+29. Average damage against 41 AC (which is harder for the rogue to get, as he doesn't have DEX and WIS to AC, and doesn't get +6 enhancement on his armour), 190 per round.
Bear in mind that even if the monk is flatfooted, he keeps his AC from WIS and class levels, and to feint you need to beat a sense motive + BAB check, which even untrained is at +27 for the monk.
DR/20 takes it from "the rogue has a chance in a straight fight, especially if he wins initiative" to "the rogue almost certainly loses".