Whirlwind using eBotD TM in D2 LoD 1.14d is the most powerful end game build, as nothing else kills Diablo, Nihl, Throne and Baal faster - these monsters, in the last 5 character levels, is where all the experience comes from. The last 5 character levels is 99.9999% of the experience a character needs to get to 99.
Unfortunately with D2R, with the lack of mathematicians on the development team, they were unable to understand how ww worked in D2 LoD so they ended up breaking whirlwind with 2 handed weapons, cutting the kill speed of 2 handed weapons virtually in half.
Since 2 weapons is the only way to go now, I don’t play D2R, however, I did try out double grief in phase blades, and they still work well. Using the right act 2 merc and weapon for him, as well as using the right weapon on switch to curse bosses, I’m confident double grief will be the fastest boss killer in the game.
End game PvM:
Gface socketed with 15/15 jewel
Highlords
2 x Grief in PB (on switch Amp curse for bosses and Lister pack)
Enigma
Duel leech ring
Raven frost
Spider
LoH
Gorerider
7 rows of Sharp g charms, torch, anni and resist charms. Resistances don’t need to be maxed with this build.
Merc:
Andy’s
CoH
Infinity (removes 83% of boss defence as well as enhances elemental damage from charms and jewelry.)
Max out:
WW
S Mastery
BO
The rest put where you want. Some max howl others max Find Item or Shout and still others buff Nat Res. Zerk, etc… I personally max Battle Cry to curse large packs, removing all their defence and half their damage.
Practice the different ww techniques: tight triangles, kiting pack edges that mana burn (though I think mana burn was removed or made it child safe), kiting around huge packs, etc…