I hear 8.5 is gonna offer Parametric modeling tools along with a robust Multi-Pass rendering setup which will export After Effects and Digital Fusion project files.
Also, a type of iterative fPrime technology will be integrated along with the following advances:
1. Faster and cleaner Area Lights
2. Faster and cleaner GI
3. Faster Bones and a more robust and true setup process
4. Instancing will be prevalent in Layout and you will be able to grow objects over time because of a new parametric tool that is hooked up to extrusions/bevels.
5. All light types will offer Shadow Map, Raytrace and Area Light shadow types.
6. nGons
7. NonDestructive/Editable Splines
8. Fully configurable UI
9. Tighter Modeler and Layout Integration (it will feel closer to 1 application)
10. AO will be a multipass option
11. Overhauled HVs
12. Object/Axis Gizmo in modeler
13. Tearable Viewport windows so you can have as many as you want
Well...that's what I heard through the grapevine anyhoo. ;D