To me, he's shown to be ALOT more efficient than Green Arrow was in JLU. GA's explosive arrows didn't even phase Mutated Eiling, while Hawkeye's arrows hurt Hulk.
And in fairness to Thor, he's shown to never give up. A good example would be Gamma World. Up against Abomination and Absorbing Man---He was even told that it was usless to fight--- "NEVER" Thor said. He also took on the MoE and was winning until Enchantress took away his hammer. Villains have to practically dog-pile to stop him from getting up (Masters of Evil, Gamma World part 1 [Mutated Wrecking Crew] and 2 [Mutated Gamma monsters]. He also showed that he was flameproof in the Wonder Man episode when AIM was taking off. Plus there was that artificial black hole he got rid of.
Plus let's not forget this series is up to Episode EIGHTEEN. Let's wait a little before writing my favorite Avenger off, hmm?