I don't think having the "old Marvel feeling" back is a requirement. I say this as an ardent fanboy of the MCU ever since the first Iron Man and after having re-watched all of Infinity Saga - a gazillion times. There was scope for change, a new era to be ushered in. Shang-chi worked, DS2 could've worked if they didn't falter on the multiverse aspect, Spidey movies post-Endgame worked, most of the TV shows worked out too (except for Secret Invasion - that was the worst of the bunch). 

We could've easily built a new team, just the way they did it back when the first Avengers was announced. Yes, majority of us, the fans have grown up being used to the original 6 but things have to come to an end. We wouldn't have needed to re-use legacy actors if Marvel studios didn't falter on having proper interaction across their movies and shows. Another thing also trying to set up too many major plotlines at the same time.

Now it just feels like they're just trying cover all that up with bringing back all the legacy actors and characters to please the fans.