All a BK gets over a normal BG is tensers in exchange for a crapton of AB and damage, but you lose the ability to smite, 1 dice of frost weapon and 1 dice of corrupt weapon. You also lose the ability to wear the cania plate and are basically forced to wear medium armor. Sure you get FW and SW but mages that have it are really common.
Maybe I'm missing something, but 6 attacks (4 at highest AB) is nothing to sneeze at. Throw in the self-buffs (including near CoT soak, respectable conceal, spell absorption, etc), serious base damage, and the ability to cast a wipe-saving spell or 2...I'll give up the smites and a die or 2 of damage as a straight BG for that. So Hands 8 got nerfed? Big deal. Unresistable damage? Who needs it; that was probably overpowered anyway. Just like anything else, if you put some thought in when you're building (or reinc correctly if you don't...) you'll be fine as a BK. We're just not AS over-the-top awesome as we used to be: now we're just plain, old awesome.
"Intelligence tells you it's raining. Wisdom tells you to get out of it"
I love my -HC- Baseborn Titan BK, he does OK in Dis. On -HC- hell runs I usually try to lv 9 grab some mobs that would be bad for the party, such as Erinyes or Rakshasas, when we don't have a mage or we want him/her to be fully concerned about dealing damage. I like soloing with it too, as with the grabby hands enemies lose their dex bonus to AC, making them easier to hit.
Also, I love being able to buff myself (GMW, keen, elemental buffs, BG buffs, etc) and to have all arcane dmg shields and Premonition at full CL, not to mention the extended displacement that may help, specially considering that on -HC- parties you'll certainly lack one "core" class, like bard, cleric, druid or mage, so being able to not depend on others for buffs is awesome. Also, with full CL tensers, you'll get the natural bonus to AC that URs lack, so usually I am able to get 130 AC with Girdle only with URs.
The only bad things are the current uselessness of lv 8 (Clenched Fist) and 6 (Forceful Hands) as they are virtually unable to land; the first one's ab and the second's one discipline DC are ridiculously low, so BKs are kind of hurt by the recent updates, though they still are one of my favourite (quasi)classes.