I think Angels stadium is suffering from the same handicaps that Dodger Stadium faced. For instance, the outfield area. It's a lot of dead space, because when they renovated it, they partially demolished and built on top of the old area. So the only usable area is pretty much on top. Nothing underneath, or inside. If you completely gut to the foundation the outfield, that's a lot of space that suddenly becomes available. From instance storage space for the groundscrew. To how about a built in restaurant in the RF wall? You go out a few hundred feet, and create a better kids zone. And how about having a bunch of food trucks in that outfield area behing LF and CF. There won't be much of a change to the looks on top, which is good. It's everything underneath and beyond that would change.
Take the same approach the Doggies did for the field level. Dig down and expand.
Expand the courtyard, so that it's multi level of space on each level as another phase in the rebuild. Then really, the last phase would be the redoing of the upper levels. Probably adding another level of box seats in the process.
a multi year plan done in sections. With the end result a stadium that has the same looks, but way more modernized.