I'm not sure that Battlerage Vigor is that bad, it's the ability to use feats and magic items to improve on it that make it ridiculous.
Compare the class features of a level 1 Battlerage Vigor Dwarven Fighter with Con 18 with a level 1 Dwarven Cleric with Wis 18.
The Fighter gains 4 temporary hit points each time he is hit with melee or close. The Cleric heals that same Fighter 31 points per encounter with Healing Word.
So, the Fighter has to get hit 8 times for Battlerage Vigor to be more potent (hit point-wise) than Healing Word.
If the Fighter is being attacked by non-minions, the opposition only has to average 8 hit points per attack to knock him unconscious.
I don't hear anyone saying that Healing Word is broken.
The real problem for me is magic items (if they exist) and feats that improve upon BRV. Improved Vigor adds 1 to 3, Dwarf Stoneblood adds +1/2 Con mod, and Bloodied Invigoration adds 2 when a Dragonborn is bloodied.
That's too much. At high level, the Dragonborn will get 12 per attack when bloodied and the Dwarf will get 15 per attack all of the time.
My house rule would be to not allow any feats or magic items to improve upon the base number of temporary hit points.
Granted, BRV is better than Fighter Weapon Talent. But, that does not bother me too much. If a PC takes a 16 Str 18 Con Dwarf BRV Fighter, that PC will have two defenses that are bad, etc. Good luck with having a not too balanced PC.