Here is some very simplified calculations:
...
Combine the attacks as you like, but the point is that you get multiplier on top of other multipliers and the damage starts ballooning. From my limited calculations the old Hunt's End combined with Sniper Shot does about 60% more damage than the new Hunt's End.
Your math looks correct, but IMO its more helpful to see how it affects a build in practice...
So here's an expanded calculation for a rough bow build (obviously actual numbers in game vary a lot depending on gear/build/focus stacks/boosts/etc..)
200 Base damage, 100% doubleshot, 400 ranged power = 2000
normal attack: 17-18*4, 19-20*6 = 1.75x
sniper shot: 15-18*6, 19-20*8 = 2.65x
pluck: 13-18*4, 19-20*6 = 2.35x
Calculating for dps added per ability (ie without the normal attack included):
Normal attack: 2000*1.75 = 3500
Old hunts end: (2000*4.2*3.25)-3500 = 23800 / 8 seconds = 2975 dps
Old hunts end+sniper shot: (2000*6.2*3.25*1.2)-3500 = 44860/ 8 seconds = 5607 dps
New hunts end: (2000*4.2*3.5)-3500 = 25900 / 9 seconds = 2878 dps
Sniper shot: (2000*2.65*1.2)-3500 = 2860 / 6 seconds = 477 dps
Pluck: (2000*2.35*1.3)+(11*32*9)-3500 = 5778/ 5 seconds = 1156 dps
New rotation total
: 4511 dps (20% nerf compared to old hunts end)
So overall its a slightly larger nerf than adrenaline got (11%), but the above build would also be doing an additional ~10k dps with base attacks+onhit+manyshot, etc... so we're actually looking at ~14511 dps vs ~15607 dps
(7% total dps nerf).
-Also to note, crusade or shadowstrike will be even better epic strikes than pluck when the buff/debuff/SA dice is relevant.
-Also, also to note, Missing the old hunts end+sniper shot combo due to lag results in much lower dps than the new lag-proof combo, so this is a huge usability benefit to consider.
I actually like the change. Its a small single target dps nerf all things considered, but opens up many more rotation and build options.