I would like to see a stamp/clone tool within the Designer app. It was explained to me in a reply to a message from your Facebook page that you didn't want too much overlap with Photo, and that having the same file format it would be easy to switch back and forth. However, the stamp tool is something that is great to have immediately on hand during composition and there are already a pretty decent number of bitmap tools in Designer, so it doesn't make sense to me that this wouldn't be in there considering how often it is needed on the fly.
I am the director of Creative Development at an international advertising agency. We design online ads to be deployed in affiliate networks, and we use this tool constantly. An example would be if a background image has say, some tree branches that are interfering with the readability on the text. In this case, I'd like to stamp out some of those branches. Same goes for the opposite, we may want more branches if the text is reversed. Then we have to use these same assets on different dimension ads, requiring more on the fly stamping. Sometimes photos are cropped in a way where the canvas is not fully covered by the background image, in which case we'd like to use this....or when a portion of an image is cropped and needs to be rebuilt.
Our environment is extremely fast paced. We can accomplish nearly everything we want to in Fireworks, though unfortunately some of the features are starting to fail since Adobe has stopped supporting it. Photoshop is a beast.... it takes so much longer to get the same result. We briefly played with the idea of using Illustrator since it is more point and click friendly in terms of selection and has a smoother work flow for rapid prototyping, but we'd still end up in Photoshop for the bitmap editing and animated gif output. Switching between apps, no matter how insignificant it may seem, is a real efficiency killer in an environment where 7,000 ads are cranked out every year.
We'd love to switch to Affinity Designer if this tool + animated gif support are added. We have over 200 major name brand clients and use both of these features extensively every day. If it works out well for us, I'd even be willing to provide a shining review of the software, as I think what has been implemented thus far is excellent!