Drupal currently supports IE11, and will do until Drupal 10 in about a year's time. Here's my proposal for how to support IE11 in a distribution without holding back from modern CSS.
Here's an example of where "less is more" sometimes. I reckon we can make the video paragraph type in LocalGov Drupal simpler by just removing the template.
Currently LocalGov Drupal relies on Bootstrap for its grid system. I think we can achieve a really nice grid system with about 30 lines of CSS. Let's see!