I haven't seen Creed yet, either of them, and that has me concerned mainly because I hadn't even heard of them until after they were released. So I can't weigh in on all the Rocky movies just yet...

... But Rocky II is what I consider to be the last real Rocky movie. That doesn't mean I don't like the others, but it means that there was a dynamic shift for the series after II.

I and II were heavy on the characters and relationships in the universe (although Creed was under-developed in I). In Rocky II they make up for that and you get to know Creed as someone who is a pompous and arrogant poser on the surface and a much deeper and respectable character underneath. And that other side to him comes out in the final bout. He's deeper than just flash, and Action Jackson did a stellar job at portraying that in a way that was essentially nonverbal at the end. It's actually a very enjoyable performance

It's also a performance that rounds his character off to the point where you can believe he did what he did in Rocky III. It adds nicely to Adrian (who after II became a regrettable side character), Paulie, and Mickey.

In the end what you have is the last great Rocky character film before the franchise drifts away to highlight boxing, only to come back to it's roots in Balboa.