One of the main reasons I migrated to HotA is it has more open skill slots than the WW build. WW requires 3 skills (Sprint, WW, Battle rage). HotA has just 2 (HotA, Battle rage), so you have more possibilities. Usual choices are WotB, fury generator, rend. But the 6th is very open - sprint, overpower, warcry, leap, stomp, charge, ?? all work in that last slot. And SOJ means you can possibly drop a fury generator. For WW, the most interesting SOJ is for throw, which doesn't synergize that well for max dps.
That said, here's the best build for farming :-D
I disagree with using killing spree for general act farming. For ubers, it definitely is useful for a 2H setup to maintain WotB. But, for act farming, the benefit provided by killing spree is marginal because the fights are too short (trash), your cc is already extremely high, and fury is not as big of an issue when you have more monsters hitting you and you can hit multiple targets more often, giving you much more fury per swing. I also run with frenzy:maniac and no hammer reduction gear, so missing a critical with hammer does not have the same consequence for me as it does for you.
Maybe if you are using smash as your rune for hammer, you have a point with killing spree being good, but I also disagree here. Thunderstrike offers superior DPS and survivability (stun). The impact area is larger, meaning trash takes much fewer swings. I have trouble dumping enough fury. I guess the downside is you take fewer swings so WotB does not reset enough? If that is the disadvantage, I'll take it!
Crushing advance + Brawler + hotA:thunderstrike is a much more potent combo for farming than killing spree + superstition + hota:smash/thunderstrike. You get more damage output and much higher mitigation with the first combo.
1) It stuns fast moving elites and goblins (if aimed properly), helping negate the primary disadvantage of the HotA build -- poor mobility.
2) It totally destroys illusionist and horde elite packs (weaknesses for HotA:smash)
3) Facilitates use of brawler (which brings its damage up to smash levels) with lower EHP totals. You can position dead center of the mob and smash away without taking damage.
4) Has a bigger splash for more aoe damage AND more fury generation off multiple hits. It shames WW AOE damage. It's not even close (for 2H or SnB setups).
The primary drawback occurs when you have only one target to hit. In these cases, you lose splash advantage and the stun advantage. If you play your cards right, this will rarely happen. Keep three targets alive as long as you can to maximize brawler uptime
For ubers where brawler simply does not work and fury is harder to generate, the smash:spree:superstition combo makes sense. Though I have done SK/Magda with thunderstrike rune, and it is pretty awesome for that fight.
If you can run killing spree + brawler, that is a different story. In that case, I think sprint may actually be a better use for that skill slot for act farming vs. killing spree. Your in combat damage will go down (overpower damage spam), but you reduce downtime between packs (and thus extend WotB more easily) and are able to chase fleeing monsters/goblin much more effectively.
Also, I wouldn't dismiss leap or ground stomp as 'crutches.' If you are running ubers with a group lacking stuns, these are massive boosts to party DPS, your own mobility, and group survivability. Since my whole friends list moved to barb, I often find myself in 4 barb ubers. Getting a couple stuns is critical for Kulle/Siege in such a party. I run leap:stun in such situations. For farming acts, these stuns are pretty terrible when compared to HotA:Thunderstrike.