Out of curiosity I was glancing at some stuff from the games I'm running that have a BRV fighter in it - he gets 5 temp each time I hit him. They ran into some Boneshard skeletons recently. They needed a 13 to hit him and effectively dealt 7.5 damage to him instead of 12.5 to his allies. With a hp pool of about 60 that means it takes about 4 hits to bloody him, and 8 hits to take him down - if given a surge and using his warforged resolve, I believe that actually turns into 12 hits to take him down. With a 40% chance to hit, that's edging up towards _30_ attacks needed to take him down, though in truth the 1.5 crits would slice off a few attacks.
In comparison, their strikers are hit on a 6 (8 with mark) and have 38 hp, falling down in just over 3 hits or about 4 attacks, 5 with them given a surge.
Your Strikers must have terrible defenses. The Striker HP indicate that they're level 4. Boneshards have +9 vs. AC, which means that your Strikers would have 15 AC. Clearly you need better defended strikers if this is the case!
In general, a BRV fighter gives up only +1 to hit for his near invulnerability in melee (and it's not like Con-fighters are weak without BRV). Even without BRV, this fighter would still take many, many more attacks to take down than your flimsy strikers.
The often repeated idea that a defender shouldn't be "too tough" is simply wrong. If a defender was offered +3 AC for free, should he turn it down because that would make him "too hard to attack?" Not a chance. What's true is that a defender shouldn't give up too much for the sake of being tough. BRV fighters give up relatively little compared to their massive increase in toughness.
And that's without even considering low damage enemies or invigorating stacking, which the house rules discussed here have been addressing. That's the 'optimal world' in which an enemy hits hard enough that BRV is used up entirely.
Besides Dwarven BRV fighters, the temp HP alone doesn't eliminate all or almost all monster damage past the first few levels. However, "the BRV fighter takes twice as many hits in melee to take down as a non-BRV fighter" isn't a good situation either.