Nothing to be worried about when going against an equiv geared pup.
Not an exact comparison, but enough for general use w/o going too too detailed in the math.
Assuming both have full uuskane, 25% haste vs 17% haste (unless pup has nsash but I think we can leave that out).
348 vs 411 delay (mnk destroyers, pup hades sainti).
Even though pup will most likely have A-, we'll ignore that and also the differences from mnk's higher str and the fstr it brings them. Pummel is a better ws, and this is being far more than generous, so we'll call it a 5% increase to mnk's ws dmg.
348 vs 411 delay
1/(348/411) = 18.1% increase in attack speed.
Assuming double march, haste, 60% haste for mnk, 52% haste for pup.
8/(100-60) = 20% increase in attack speed from haste
1.20 x 1.181 = 41.72% of an increase in attack speed that mnk has in any pt w/ a brd and a rdm.
Since we're calling pummel a 5% increase, mnk is now
36.72% ahead.
This means, the maton alone would have to do 36.72% of a mnk's dmg just to break even w/ a mnk, yet alone defeat one. Also doesn't account for focus, counters, ect on the mnk's end.
Looking at the current comparison, pup really needed this overhaul just to compete, imo.
Edit: Doesn't account for the delay gained by 3+ maneuvers a minute, either.