This comparison must have been created by React dev. Learning curve easier for React than Angular? There is no way this is true with all those strange quirks of React and its own js-xml like language. Angular only adds two parenthesis to bind data to the HTML, rest is mostly like pure HTML/JS/CSS which is much easier for newbies. (being webdev for *teen years I haven't seen anything uglier than React my whole programmer life)
Anyway, as for the new dashboard, with current one I struggled to modify UI via node template when I wanted to add a clock in the top bar or some additional info like battery level - so no separate widget but base layout change - would be good to allow such action with the new approach.
Maybe a neat idea for transition period and for abandoned UI nodes would be to add a wrapper widget that you can place in the new dashboard and attach the old UI node to it? A bit similar to iframe node showing Grafana widgets? With such wrapper node backward compatibility won't be such a burden for the new dashboard.
