One big change in Source2 is the resource (models, material, textures) pipeline. My original intention was to have it so you could stick your fbx and png files in your addon and load them and it'd all be good.
On reflection I think S2's tools are way too good for us to discard. This is a lot of work because a LOT of code assumes you're using the game/content folder layout Valve use - and I don't want to work like that. So I'm working on bending it into a shape that will work for us all going forward.
This isn't to say that creating assets at runtime isn't going to be possible. It's still a big part of the plan.
