The reason why I would like to give feedback on your rendering is because I like your building design, but the renderings are not showing how great your idea is. That is what my professor said to me 10 years ago, and that is what got me into rendering. I hope to give you the same push :).
First, it's very hard to do bird perspectives, because of the amount of things that you need to include in the image. The biggest problem is the existing surrounding area, that would need to be modeled, if there is no satellite data to import (and most often that doesn't look good). I would suggest, in those cases, to make a smart decision and to go with some "stylized" renderings. For example, rendering that looks like a maquette, with stylized assets (vegetation, cars, people....). Or, maybe going for a look that the surrounding is simplified, and your building (and everything on the property where the building is located), is modeled in detail and looks realistic. That way, we wouldn't have the empty grass around the building (like in your case), but at least some details that make the image interesting.
But, if there is enough time, you could also go with adding detail to the surrounding. Here would be important to try and stay true to the real location. Finding the right 3d models, and trying to find a big variate of them. Use scatter tools to avoid placing the assets manually, and to add difference in their scale and rotation. People is something that is really missing in your renderings. I don't like placing a lot of people in renderings, but in a perspective like this it's a must. You could also try to use scatter tools to place them, and if you see that something is wrong (direction in which they are walking), it's easy to adjust it manually afterward. Difference in textures, would make a huge difference, especially in roads and pavements.
Try adding mood to your images. You gave a great description of what led you to design your building the way you did. Translate that to the rendering. For example, performances are usually held at night, go for a night/dusk scene. A lot of people came with cars, so the parking lot is almost full. Crowd of people going to the entrance and the artificial light from the interior is lighting up the entrance part...
I will add a couple of references which I would choose to follow for this type of perspective.
I don't know how important renderings are to you, but I hope this feedback help you at least a bit :)
