Also, if I weren't a battlerager-type fighter, I would have a higher Strength (because I would not need the super CON) and I would be using a sword rather than an axe. So, in reality, we're looking at a difference of 3 to hit, not just one. I'd also be wearing armor better than chain, and would have chosen powers that are better than then invigorating ones. It's not just a matter of choosing battlerage vigor instead of the +1 to hit with a weapon - it's a completely different build strategy, making the cost higher than just at single bonus to hit.
You don't have to do
any of those things. Indeed, if the BR was FORCED to fight in Chainmail, not to use a shield and to use axes or hammer, it might be balanced.
He'd get crazy temp hp but be at -2 (or more) to hit, -3 to AC and -2 Reflex over a sword and board fighter. Maybe that's balanced.
But as is, you shouldn't go chain for a +1 to damage at any rate. +1 to damage for -1 to AC is a sucker's tradeoff anyway.
Considering you will lose +1 to hit, it's even logical to keep using a sword. After all, hitting with crushing surge and the like to stack THP is a concern.
You don't even have to sacrifice your strenght.
You can stay in scale, use a bastard sword as before and take 14 con like the typical fighter. Just take the improved battle vigor feat. You now crush the identically built fighter by having identical stats except for a -1 to hit in exchange for gaining lots of temp hp. You'll hit almost as much. In a typical encounter, you can easily go the whole combat without missing by 1 but a fighter almost never go the whole fight without getting hit. So imagine these two identical fighters in the same encounter, one BRV, one not. One dishing slightly increased damage (which can only be observed in the long run and might not come up at all in the encounter) while the other is much harder to bring down. Even at 3hp per hit, it means that when the standard fighter is going down, the other still has at least one, probably two to three solid hit in him (which, btw, gives him a chance to do a few more attacks and bumps up his damage in the long run on par or even over that of the weapon talent fighter).
They don't seem balanced to me.
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To balance out the Battle rager without getting rid of the feature altogether, I would force them in lighter armor, get rid of the 'You get THP when you get hit' mechanic and replace it with 'You get THP when you kill stuff'. The rager would get THP either when he kills an opponant.
It would force them to focus on offense. That's more rager.
Because another thing I hate about the current rager is that he doesn't behave at all like a rager; he's just the ultimate obstacle. He plays like a rock. He has no incentive to run around agressively on the battlefield to kill stuff.