The new mesh compiler allows to use models as meshes and then shadows can be baked in ED just like with any block.

Imho the huge advantage of blocks is the easiness of texturing them. Models need to be unwrapped and that can be a very time consuming task. More freedom in level creation has its price.

CSG substract is fine if used properly. You should never use it for holes, windows, caves, ... though. This is a real killer.
If you need to cut off an edge of a block, or the top of some cone, it normally works just great. Just don't overdo it.