After observing and speaking with several brokers, I also noted that part of their challenge was the multitude of ways that a client could communicate with them - even just keeping track of emails, texts, and automated messages from real estate online posting sites was difficult. Thus, having all communications from one client aggregated and displayed together is more helpful than having to switch between different communication channels.
In order to mockup the proposed application with these core features, I first sketched out general screen flows.
To deal with the volume of responses that often required automated or similar responses, I incorporated some simple AI to determine when an automated script could be selected for a response, while still giving the broker the ability to customize the message if need be. More importantly, I added a feature that enabled brokers to sort, flag and search their messages. Boiled down, these needs became some of the core features for my the design.