Shields give a shield bonus, the shield bonus does not stack. So now it's the dude with one shield and a weapon.
I've been trying to figure out how I would build a two-weapon Fighter/Rogue with 7 feats, and I'm always happier with a weapon-and-shield fighter. Here's where five feats go:
Weapon Finesse (mandatory for DEX guy)
Weapon Focus
Weapon Specialization
Improved Critical
Improved Initiative
Two feats left. Two-weapon fighter takes:
Two-Weapon Fighting
Two-Weapon Defense
Weapon and Shield fighter could take:
Two-Weapon Fighting
Improved Shield Bash
or, my preference:
Dodge (+1 AC vs. one opponent)
Power Attack (extra damage when you can afford to reduce your chance to hit)
I'm really not that impressed with the feat chains to Whirlwind Attack or Great Cleave.
I looked at taking Duelist, but Duelists are terrible compared to weapon and shield guy. (Duelists only get the AC bonus when unarmored and without a shield. Blech.)
To give the two-weapon fighter up to the same defense as weapon & shield fighter, you need a weapon with Defending, and it's not worthwhile. e.g. Compare Heavy Shield +2 of Bashing (+4 AC _and_ +1 weapon causing d8 damage with Improved Shield Bash) vs. a Defending +3 Weapon (+4 AC with two-weapon defense _or_ +3 weapon and +1 AC with two-weapon defense). They cost respectively 9,000gp and 32,000gp.
So the weapon and shield fighter is 23,000gp better off. Hmm, let's buy a +4 Belt of Giant Strength. The weapon and shield fighter is much better off.