We will definitely be including waterfall display modes in SmartSDR. It is our understanding that this is one of the most desired features that is currently not in SmartSDR, so we currently have elevated the priority on this feature.
Feel free to add an idea topic here on this subject (or other features) which will allow others to vote on the idea. This will help to align our development efforts with the desires of the community. Thanks for letting us know your thoughts!