typically people would use hdri as an environment map to get natural (interesting) reflections in your windows.
Otherwise, martians like me, would add some interior to make the scene more interesting and do the reflections in Photoshop. :p
Otherwise, yes, since Corona works very well with HDRI, you should take advantage of that. Unfortunately, my main pipeline is still MR and MR in 3DS Max is not the best at handling HDRI.
Another thing, you should add some more environment, some more trees, etc. To make it more dramatic, change the time of the day to something that would be more plausible to the golden hour of photography, where you would get long shadows and warm colors. Then I'd add lights inside the building (which Corona handles beautifully just by adding a few lights here and there).
Also, add some reflections to the asphalt and if you are going to do the scene at the golden hour, light up trees and bushes and the key elements of your building.
Anyhow, hope that helps.
