Ragebringer is the great weapon that you hate to love and love to hate.
Anyway.
Tonight I looted a blah blah of Corrupted Mana (12+1/16) off Glyphed in Ssra. My usual line up is Tendonslicer (15/20) and RB (15/25), with RB being the haste. My only backup haste item is a (sigh) banked FBSS (21 percent haste).
Now, calculating this out we can see that TS+Whip+FBSS sucks. However:
Given the choice between these two setups, which is preferable until I can get sufficient haste to make TS/Whip a viable combination (or until Khal drops and I can die happy)?
Well, to be quite honest, RB will be a better offhander due to the attack for a really long time yet. 12.25/16 is a .766 ratio which is right around the cutoff for bagging RB with 1450+ attack and 40%+ haste, assuming relavent AAs and a superior mainhand. Without knowing your AAs nor attack level I would still have to presume that TS/RB will be your best combonation for some time yet. (I'd note again that 12+1 is not 13 but closer to 12.25 or 12.33 depending on the dataset you like.)
Even if you had no Ferocity and did have Ambi/Sinister Strikes with maxed worn attack, I'd be a little shocked to see RB/Whip ever outperform TS/RB. TS/Whip becomes preferred at ~1450 attack and with 40% haste, although it's still pretty marginal at that point.
