Google’s Flutter = React + Java Swing
David Ford

Flutter needs to adopt the equivalent of React’s JSX. Without it, it’s quite painful to type out the widget/component hierarchy and it makes developing GUI builders complicated (; it also makes the code much harder to read and hence to maintain in the future. React (with React Native) brought cross platform UI development to a whole new level and that is the bar to measure yourself against. Be better than React Native and make sure you are designer friendly too; i.e. easy to import assets from Sketch, Principle, Atomic, Flinto, Framer, etc.