Wasp's was accurate. He offensive power is low.
Hawkeye may be the best bowman on Earth but he's still just a normal human in very good shape.
Cap, medium, yeah, since he's a super soldier. His offensive power is brute force, and other Avengers outdo him there.
If you're just assessing physical power, sure. But Doom's henchwoman's analyses overlooked character traits. Someone can be less physically powerful than others yet still be more clever, more cunning, a better leader, etc. Captain America, Iron Man, and Thor are on three wildly different levels of power, but they're more or less equal as leaders of the Avengers because of their other qualities -- Tony's intelligence and inventiveness, Steve's strategic experience and ability to inspire and rally others. And I'm not too familiar with Wasp in the comics, but in this show, Jan has shown herself to be quite clever, creative, and relentless in action, and is often able to pull off victories that don't seem possible based on relative power levels alone. As for Hawkeye... well, I don't know. Stubbornness and attitude? Whatever it is he has, he's managed to hold his own alongside the heavy hitters.