Why so many people complain about comic books they don't read?

[SeeDarkly_X]

That's the idea. However, how separable are these titles from the characters that acquired the title? That is if applying "Captain America" to another person, who hasn't fought Hydra in WWII or been the worlds first super soldier or the title "Thor" to someone who is taking up the hammer. It seems from what I know of these characters that you are losing a lot and I haven't seen enough of the comic to see why we need some specifically to take the same title, perhaps job description? when there is so many other heroes in the marvel universe. I could understand someone filling in for batman or superman and taking the title as well, because in certain media, they are the only ones filling a particular role, there is no other protector of gotham or the universe in quite the way these characters do it (at least if you from some very narrow film adaptions). but from what I've seen of marvel, there are always so many superheroes, someone with something new can always fill in. Particularly, why isn't Falcon enough as Falcon? Why would he adopt a new name, or require a new title?

Falcon IS enough as Falcon... but Falcon is also not iconic in the same way that Captain America is.
Falcon did not punch Hitler in the face, for e.g.
However... this is about Sam Wilson in the absence of Steve Rogers as Captain America, and thus becomes a story about carrying on the mantle, living up to the standard set by his friend and role model, striving to honor the role and achieve something even greater in order to maintain the presence of Captain America in the world.
And yes... on balance being "Captain America" is absolutely "greater" than being "Falcon" in the ongoing story of the MCU as it exists.
Meanwhile Rogers's story becomes about being a mentor and dealing with his loss and the possibility that he may never regain the power given him by the super-soldier serum while still contributing to the fight.

Odinson? Well he COULD quest to become worthy again... or he might just fade into the background for a while and drown his misery in beer, ending up homeless on the streets like the Submariner did when the FF found him years after WWII.
"Boohoo, daddy lied to me about my sister and gave my hammer away, boo hoo." *shrug*
Lots of interesting story possibilities.