A nice tight bridge to Godot should get most of the way to healing that, version 1.1 will add a visual shader editor (read, node-based) , numerous usability enhancements, and several other new features. Version 1.2 will have enhanced navmesh support and high-quality filter effects such as SSAO (they’re going for UE4 quality here).
Face it, it turns out that it’s not in the interest in Ton and co. to have a full, built-in game dev. environment, even if they could develop the BGE more, it will always be handicapped by the GPL in terms of available platforms and the way that people can sell their games (numerous threads have shown it to be a major catch).
In the end, the BGE in a sense, even back in the day, was just another free option with strings attached (the GPL), but with new options emerging in FOSS that give total freedom in game distribution, I don’t know if it has to be Blender’s job to fill the void.