It was a yoke
But you're right, it's really good in TBC (although I'd prefer mutilate for the first seasons).
The reason why it is not used at all is because going that deep into the combat tree to get the Mace Spec points forces you to chose between getting Hemo & Prep in Sub or getting the key talents in Assa. You can't pvp efficiently if you have to give up on these.
If you go for Hemo & Prep like the 2 specs you suggested you won't have Relentless Strikes, Ruthlessness, Malice, Lethality (even though its effect is largely misunderstood) & CB.
If you go for these talents you won't have Hemo nor Prep and using SS as main CP builder simply sucks.
It's a lolspec against other melees when you get good gear though.