I'm curious what the deal is with Steve Rogers these days. I know he lost his Super-Soldier Serum somehow, so he's supposed to be a 95-year old in appearance as well as age, but there's quite the variety to how he's presented.
In most of the Avengers titles, he has essentially the same build, it's just the face has a lot more lines and his hair is grey or white. But he's in his Commander Steve Rogers get-up, rocking some pretty decent muscles and getting in the middle of battles. But those are the big event books, and Steve is supposed to be leading the opposition to the Illuminati and their blow up worlds for ultimately no purpose. Maybe it undercuts that if he can't be at the forefront, directly fighting for what he believes in.
You might have guessed I prefer the third type, since it makes a certain amount of sense to me that 95-year old Steve Rogers would be in decent shape, but not "leap off building and jump kick a guy off the top of a moving vehicle" condition. It still allows him to be around other heroes, but maybe in a more advisory role, supporting or encouraging. Steve Rogers is generally portrayed as a good guy, capable of being easygoing and friendly. Play up his experience and his personality, rather than his ability to do cool stuff with the shield.