Julz, your post sounds a bit theoretically. And in this case I totally agree with you. You can do all this. You can write the shaders. You even say it is "dediculously easy". I am sure that most users will disagree here since only little know vector and matrice mathematics.
And yes - you can add shadowmaps with Ventilators plugin.

I know all this since we work on a prototype with exactly those techniques and because of that I can tell you that in practice there are more problems then you might think of.

You will get heavy problems when you want to make a level with more than one texture and more than one uv. FBX and obj import does not support more uv's and shaders get problems with many textures and uv's.
When you pack all into one texture and one uv then you have some problems with modelling and level design.

Besides that it is not that easy to write shaders for AO, depth of field, dynamic shadows an much more in a small team. It takes much time and effort and will not compete with experienced shader developers.

We do our best and will show our progress in the future. But I still would suggest to argue a bit more realistically and not only with the usual term that I read since several years: "It can be done"

Regarding radiosity on blocks:
This ist still not available and had some light bleeding in the last images. And I doubt you can combine it with shaders. And then you still are limited to point lights with linear fall-offs (no spot lights, no area lights, no squared falloffs). This is not a good lighting-toolset.