Well, even with Mythic boost it's not totally clear cut. A current Mandalic Stab set could easily have 16% TA, which would be 1.32 swings/hand. With Mythic AM3, it would be 1.86 swings on the main hand. Overstating additional attacks/round benefits Mandalic in this comparison, so I'm giving both AM3 and going with a highish estimation of additional attack amount.

Mandalic 1000 TP = (5+(8.5-5)/4+0.86+1.32)*1.3 = 10.47 fTP total with +66% attack boost
Rudra's 1000 TP = (6+(15-6)/4+0.86+1.32) = 10.43 fTP total with 20% more DEX mod

So depending on mob defense, Mandalic might be better or Rudra's might be better. Against most current content with reasonable buff levels for the content, I'd guess that Rudra's is better despite the fact that's not being used properly (going at 1000 TP) in this example. Mandalic kind of got the short end of the stick this update, but it's good that it got buffed so it's less painful to activate AM3 with. It's still respectable, but Rudra's is just crazy.