I liked Captain America for a time as a child, but he wasn't my favorite b/c he took a serum to become a hero, unlike having an accident that you then have to learn to live with.

I'm not clear on everything the serum gave Cap. It's possible he had a good tactical mind before taking the serum, but if he hadn't taken the serum, he would've been 4F, not had the chance to exercise his military mind.

OTOH, I kind of like the idea that he volunteered to take a one-of-a-kind, experimental serum when maybe no one else would, but since then we have all these others who've taken the serum.

I also never understood why Cap would throw his shield. It's like the best shield ever. Why not keep it and use it mostly to shield yourself?

I do like that, by having others who've taken the serum, you can differentiate their personalities from Steve Rogers' and show that he, Sam, and Bucky would use their powers responsibly while others wouldn't.

General question of superhero physics: Can someone possibly lift 10-30 tons bare-handed and have the physical build of Spider-Man, or other heroes of supposedly similar strength? Wouldn't you need a build closer to the Juggernaut's?