Isn't that to be expected from a next gen release? More system memory = many more animations, moves etc. You wouldn't expect any less than an improvement in the combat system. The devs said as much- for example, the grapple move, they wanted to implement in 2, but didn't have the system resources available on PS2 so threw it in for 3.
Again, all this is to be expected and that's why it's still a GOOD GAME, just not great, like the others.
There is no progress in thinking behind the level design. Instead, they've demonstrably went backwards in that respect.