Some of those are valid criticisms, but I think some of them are unfair. Captain America has been used a lot of different ways over the years, varying between Jingoism to social commentary to just straight superheroics. He can be used poorly, just like any other character.
Cap is usually written to be the best of us. A man who answered a calling and rose to a challenge, but as often as not its not his super-powers that make him the hero, but his determination and will. If you think he's bland, then I wonder how much of him you've actually read, other than stuff like Civil War. I'm not a huge fan of Cap, but I like him well enough.
Cap isn't Batman...he's more like Batman mixed with Superman. Cap is a super-soldier, not just a martial-artist. Bats is easily a better fighter, but Cap is super-humanly strong and tough. And honestly, trying to make the case that Cap shouldn't get involved in fighting Ultron or Loki because he doesn't have Thor's powers seems kinda odd when you don't seem to hold Batman to the same standard (because it's not Batman's gadgets that make him a threat to Darkseid...it's his brain).
As for strawmen and not acting on them? Name me another hero who abandoned his identity in disillusionment and protest over his goverment's actions. (see Secret Empire, Nomad). Cap had a black partner at a time when DC was asking if readers were 'interested in seeing more black people' in comics. Cap has repeatedly questioned the government's actions and military adventurism. But Cap is a soldier and understands that supporting fellow soldiers and disagreeing with American foreign policy are not mutually exclusive. Hell, I really didn't like Civil War, but the main thrust of the series is that Cap thinks that registration act is immoral and unconstitutional and engages in civil disobedience (albeit in a stupid way that doesn't ring true for Cap, but that's neither here nor there, since legal wrangling in Congress doesn't involve punching Iron Man).
I grant you, in recent years Cap has been elevated to Legendary status amongst many of the characters of the MU. But in truth, he started that way when they thawed him out in the 60s and he's pretty much been that way off and on for years. Cap HAS had an interesting cast and life...but in a lot of stuff (like the Invaders and in the Avengers), he's just Cap all the time, which reduces his interest level. But I still laugh when I think of what happened the first time Cap saw Star Wars. Cap is all about being human. I'm kind of surprised you feel otherwise.