Terrifying rage isn't the barb rage that should get a buff, if any of them are, except maybe changing the fear duration to 4 rounds instead of 1d3 so it's consistent with the other fear-based spells and effects on Amia same as I said in my posts the
last time this was brought up for discussion. (Also take a look there because I go over some of the DC potential and if an "average" barb build gets mid 20 terrifying rage DC, then they are either picking no barb levels or doing something wrong. 24 level barb with 33 intimidate, both focus feats and 16 base con gets DC 36)
Barbarians as a class already get a ton of stuff which makes them on average have more HP, AB, Damage, and AC than any other melee based class if you build them that way, with the exception of Dragon Disciple, with the downside of being feat starved.
The fact that terrifying rage was fixed so that it can't be exploited by running around the edge of the aura to spam re-rolls made it more balanced, not useless. It's still one of the best utility feats to grab for any melee class.
I mean for the penalty of -4 dodge AC, a level 24 barbarian gets +12 damage, +3 fort, 24 HP, 50% movementspeed bonus (doesn't stack with haste) and 1 attack per round (STACKS with haste, made at full AB same as haste). That extra attack alone puts them above just about any other melee based class, and if that isn't your cup of tea then you have the standard rage which gives +6 AB, +4 damage, +3 will and fort or the unyielding one which gives you +6 regen, +4 Dodge AC, +3 all saves, 72 temp HP and +3 AB. That +3 AB bonus is the same amount of AB as a level 14 WM gets btw so you get more AC, saves and HP than a WM but with less powerful crits OR you can go with the ferocity rage, get 3 less ab & 4 less AC than them but more damage, higher fort to save against dev, natural movementspeed that doesn't end when your haste pot does, and 1 extra attack per round made at FULL AB. That extra attack per round at full AB means that you can potentially out damage a WM while retaining the flexability to pick the best rage for your build and the situation you are in.