BGE and Blender Render (BI) both are in heaven
. They played a major role for B4W and will play until we let them go
Since Blend4Web uses BI viewport and the shader system is really powerful and fits Web, I think we will make a fallback for this system.
About 2.8 compatibility there are a set of issues we are going to cover:
1) Viewport - create WebGL responsive preview in Blender
2) Fix data issues - since there is no BI/BGE nomore, there is no variables in Blender environment which B4W are using now; fix this
3) There are some changes in mesh storing. We should update our code to use modern.
4) Create fallback for BI nodes - rewrite them using Pynodes
5) New collections - add support for them
These changes are most important for Blend4Web and Blender 2.8 compatibility. They will make B4W usable in Blender 2.8. And the next stage is to improve PBR-pipeline which is native for Eevee.