Oblation is a weird skill in that, while it does feel very weak and unsatisfying, it's also right on the cusp of being powerful with basically any small buff, in any direction:
If it were 15% mitigation instead of 10%, it would be strong.
If it had a 15s duration instead of 10s, it would be strong.
If the cooldown were reduced from 60s to 30s or even 45s, it would be strong.
If it had a heal attached, it would be strong.
If it had a Blood Price effect, it would be strong.
On the one hand, I can sort of understand why it isn't particularly strong: Given that you get it at level 82, the same level that Sheltron, Raw Intutition, and Heart of Stone get their upgrades, it's pretty obviously meant to be DRK's version of a companion effect to TBN - but since TBN at a baseline is considerably stronger than the pre-upgrade versions of those skills, it makes sense that its "upgrade" would be relatively small in comparison.
On the other hand, being considerably weaker than Knight's Resolve/Benediction, Stem the Flow/Tide, or Clarity/Catharsis of Corundum and having a full 60-second cooldown when those other buffs are applied on every use of their respective skills, is a bitter pill to swallow, and having a second charge doesn't really make things square.
I wonder if the best thing for it might be for TBN to get a trait at 82 that reduces the cooldown on Oblation by 30 seconds when it breaks, or even just expires.