Tanking really only consists of two things:
- Grabbing (and holding) aggro, which mostly comes from maxing out Intimidate + your threat amp.
- Not dying, which means being able to take all the hits coming from all the aggro you just grabbed. High HPs, high AC, high saves, high PRR/MRR, etc. Brownie points if you're also able to self-heal faster than you take damage, but not a hard requirement if you're building for teamplay.
S&B builds have a few advantages to both factors: higher AC, more PRR/MRR (including the
shield multiplier), shield-specific bonuses from Vanguard / Stalwart Defender / Divine Crusader / Unyielding Sentinel, etc. Which is why if someone's making a serious raid or Hardcore tank, they're almost always going S&B.
That said, nothing stops you from making a 2H fighter which is tank
ier than normal: e.g., fighter 20 with max Heavy Armor feats and 41 Stalwart Defender / 31 Kensei (One Cut) / 8 Harper Agent (Know the Angles). Trade some DPS for added defenses, though obviously not the shield-specific ones.
For maximum
gimpiness roleplay tankitude: CON-based dwarf with TYWA and Dragonmark for Radiant Forcefield (aka "bubbles"). 41 Stalwart D / 18 dwarf / 11 Kensei (Strike w/No Thought) to start, sprinkle remaining APs as you see fit. Also works for 2H barbarian tank.