It would be nice to be able to set the window size of the engine window on a computer to test how a game scales from one aspect ratio or resolution to another. Even nicer would be to also have som presets like “iPhone Landscape”, “iPhone Portrait” etc in a menu to pick from.
This is even more so when uploading to the app stores and they want videos and screenshots of the game in certain sizes.
EDIT: To be clear - I am not talking about game resolution here