Designer and Photo are great apps for designing presentation boards for architectural puropses.
Everyone who knows the workflow for this kind of job understand the demand of app that handles both vector and raster images. Usually you import pdf from cad and start to add trees, sky images and text, especially when you are working with facades or sections.
It is so great that file format is same in Photo and Designer. You can tweak raster images easily and modify vector lines without pain.
But I am missing one special feature in Designer: select similar line weight, colour, line type and so on. I hope that you can add this feature soon.