Precision started nailing the coffin on rage builds and Epic Precision finished the job. It's really starting to look like a comeback for the old Heavy Pick and G.Axe builds because when it takes a nat-20 to hit, it's going to be a crit.
IMHO, the problem is that content is tuned for ultra-high accuracy WITH ePrecision to graze on 2. The content should be tuned for RAGE builds with Power Attack grazing on 2~3 with Precision build getting that tiny extra bump to never graze. And, content is never revisited, particularly for tuning things. This will make it hard to "balance" rage+power against D&D fundamentals, which use accuracy as the tuning point.
Personally, I'd also seriously consider applying the attribute damage modifier or something similar to all bonus damage (eg. THF gets 2.5, SWF 1.75, TWF OH gets 0.5). Currently, only power-attack and a few tree nodes are adjusted by style.
VKF Kukri with Frenzied Berserker was THE TWF build until Dragonlord. It's still better in some ways, but Rage+Power is pathetic compared to Trance+Roar. There's no substitute for Accuracy and Helpless is just cherry.