As a matter of fact, here's a similarly blunt statement that I will proceed to defend with facts: "Spending a feat to gain the ability to make two attacks with a light weapon with a -2 penalty to hit and half damage with the off-hand is just insane."
Defense: Any melee-oriented character can, without spending a feat, pick up a two-handed weapon and attack at no penalty to hit to deal more damage.
For example, Dirk Diggler, a 1st level Warrior has taken the Two-Weapon Fighting feat and wields a Handaxe and a Shortsword. He has a Strength score of 18. When he attacks he may make two attacks at +3 to hit and deals 1d6+4 damage with the first and 1d6+2 with the second.
Meanwhile, Grok Smasksh, another 1st level Warrior picks up a Greataxe. He hasn't even thought about what feat he might take. He also has a Strength score of 18. When he attacks he makes one attack at +5 to hit and deals 1d12+6 damage.
Comparatively, Dirk deals 10% less damage than Grok because of his lower attack bonus. Dirk then deals an average of 11.7 damage per round, while Grok deals 12.5.
Against, say, DR 2/magic, Dirk's damage falls to 7.7 per round, while Grok deals 10.5.