We are planning on replacing OpenLayers with CesiumJS, however, we cannot be 100% sure our clients are going to have robust-enough video cards to support WebGL. We are only planning on using CesiumJS's 2D mapping features, is there a way to get around having a video card with WebGL (or OpenGL) capabilities?
Core Cesium is based solely on WebGL, and requires it. But there's a fork called TerriaJS that uses Leaflet as its 2D fallback for non-WebGL systems. TerriaJS was built for Australia's National Map, and can be installed via npm.