I think this is a given, the 200 level was already replaced with these seats. You'll notice they are a darker blue. That alone will make the stadium look fresher.
I think they could also do some cool stuff with the outfield. There was talk of elevated bullpens and an asymmetrical outfield wall. I bet they'll do something cool with the hitters eye and some of that blank space between the wall and the outfield seats to make it flow better. Concourses will be re-done i'd imagine, and they desperately need a food overhaul.