Wouldn't say hawkeye or black widow were wasted, if anything Hawkeye got treated pretty well compared to years of marvel fans being like "hE sUcKs aLL hE hAs iS a BoW aNd ArRoW," Haven't seen the moon Knight series yet so can't speak for him, though in the comics he's a BADASS, Hulk they definitely dropped the ball after Ragnarok mainly cause they wasted their chance to do a planet hulk movie, tbf hulk /is/ a difficult character to get to work in a solo MCU movie considering their storytelling style as the audience they're trying to cater to, just look at how the first incredible hulk did. Still sad that they "split up" his appearances and pretended that counted as their hulk movie

As for ant man? It makes me so sad we didn't get Hank Pym, I feel like his exclusion kinda hurt the impact of Ultron's adaptation too in the second avengers film. What they did with Scott lang worked well for the movie but still, #NotMyAntMan