I think to is that the first Rocky at least spent a lot more time with Rocky in his daily life. He was a poor dude, and his life was hard.

It's been quite a while since I saw the first Creed but the guy had a nice office job and seemingly the support of Apollo's wife to where he really had no reason to fight other than to live up to the Creed name but he also fears it. Rocky on the other hand HAD to fight to survive and even when we see him he's struggling.

I liked the first Creed movie enough but yeah there are no memorable songs that just brings is all together.