So far I've completed two of the buildings that have been converted to bars and have the bleachers on top, and I've also completed the building with the famous Budweiser roof. I was reading the other day that there is no longer a Budweiser advertisement across the top of the red roof at the real Wrigley Field, but it will remain at this one! I'll eventually add "Budweiser" in white to the red rooftop.
The two buildings on the left have converted their third floors, adding giant windows from which you can view the game. If you look closely there are a few fans in there taking in an afternoon game. The bleachers are a little empty, but they'll fill up as I acquire more "minifigs" which is what the Lego people are technically called (see - I'm learning!).
I think I'm roughly around 15,000 total pieces so far. I still have to go back and add details to the left and centerfield bleachers, but I'm waiting to find some particular pieces. In the meantime, I've got four more buildings on Waveland to add (three to the left of the existing structures and one to the right of the Bud rooftop) and several more that I can build on Sheffield Ave, which is behind the right field bleachers.