What else could you do with his character? Plenty.
You could bring back Red Skull or introduce Baron Zemo.
He has 7 decade history.
eh, again, what else can Red Skull do differently than what he did in TFA? I'd be down for Zemo, but again, he'd just be cut & paste Red Skull. I really like the espionage theme they're going with for this movie and that's why my interest is high.
And so what if he has 70 years of history, his best story-arcs he had were coming back from the dead and Winter Soldier. Man out of time and his origins were already covered. Besides Baron Zemo, what interesting story has he ever had?
A-hole Cap from Ultimates was cool but he can't be the same as Evans/Rogers, so if you were allowed to let Bucky rock as Cap, how would that not be awesome?
Forgot the name of the story but Cap has quit many times, they can that story. Now that Falcon is in the mix, it can easily be a Cap & Falcon movie and there are plenty of books they can cover with that team up. Cap has also "died" several times, Rebirth might be a good place to reintroduce Red Skull.
Ans speaking for Red Skull, you really think they can only come up with one story involving him? I mean really? You think all he could be in the film is trying to get the Tesseract?
Hell they can put both Zeom and Skull in the film together and have a Mexican stand-off.
And the hell is so fascinating about Bucky being Cap? I mean seriously, you want to see him don Caps shield for a minute as you stated and that is it, that accomplishes absolutely nothing.
At the end of the day you are crazy if you think Cap is as shallow as simply being a man lost out of time type of story.