I've put a lot of thought around this build.
First, the assumptions:
- I'll always be in a group, be it with friends or just public games.
- Allies aren't stupid enough to disregard their own defensive skills. I'll do my best to save them, but I ain't responsible for their life, not like an MMO tank.
- The abilities and runes won't change (much) other than required level which doesn't matter in a level 60 build.
- Inferno monsters, even the regular "white" ones, have enough health to withstand a 15-second onslaught.
- Frenzy buff stacks additively to dual wield and other IAS, giving diminishing returns on the latters. In other words, Frenzy is sword & board-friendly, and Inferno-friendly where you'll want defensive stats rather than IAS.
Second, some notes:
- Main gearing idea is to have as much +life on hit as possible, sword & board style, which should make Frenzy that much safer against uniques and bosses.
- Ancient Spear's primary use is to bring ranged monsters, especially champions, uniques and bosses, to me so I can stun and Frenzy them down.
- Ancient Spear(Dread Spear)'s healing is roughly equivalent to an instant Rend(Blood Lust) on 6 targets. Rend's range being rather small, coupled with the inability to use it while running from danger, makes it less than optimal in Inferno, especially in boss fights where the number of targets will be limited.
- Some go for Bloodthirst to provide healing, but I think this is a bad idea especially in a group situation. Not only the abondance of defensive abilities restrict your ability to deal damage (3% of damage done becomes very small), but the heal only affects you. That's why I go for Pound of Flesh; 25% more health globes isn't a joke, and they'll most likely top you off, and they'll heal your allies too!
- I've seen first-hand what Bash(Clobber) does on the Skeleton King fight, and it's amazing. That's why I went for Frenzy(Smite).
- Situational awareness is key to completing Inferno. Improvisation and survival instincts are required to come out of unforeseen situations alive.
Third, the goal: To have everything you need to deal with just about any situation, in order to never swap abilities and thus keep the Nephalem Valor buff.
Here are the situations I thought about.
If a monster comes out of a barrel, just Frenzy it down.
Pack of regular monsters
Leap into it, move out a bit, Seismic Slam as many as possible, Ancient Spear one and Frenzy it down until the pack is getting close or moving towards an ally, at which point I'll get in there and Ground Stomp + Threatening Shout, then move out and Seismic Slam 2-3 times. Rinse & repeat.
With or without a unique (yellow) monster, the idea is to do roughly the same as a regular pack except to always keep a stun off cooldown for "ZOMG" moments like being trapped by a waller.
I would lead with Ancient Spear and start Frenzying that monster down, then Leap out to the rest of the pack and use Threatening Shout, move out, Seismic Slam a few times. Switch between stuns as the situation dictates. Rinse & repeat.
See below for dealing with the unique monster, if there's one.
Uniques and bosses
Save Ancient Spear for when healing is needed, or if an ally is in danger. Leap in and Threatening Shout, then Frenzy until health is dangerously low, then Ground Stomp and run to gather health globes (Pound of Flesh should help a lot here). Rinse & repeat.
If somehow the unique/boss is immune to stun, definitely save Leap for escape purposes. And if there are adds, as in the Skeleton King fight, use the generated fury to handle them with Seismic Slam.
And if Ancient Spear doesn't work on the boss, at least its damage (and rune healing) will work.