The change from shader 2.0 to shader 3.0 means absolutely fuck all on its own merit. They have a TON of work to do to optimize everything using the new functionality.
What this allows the devs to do is do cool shit with new optimized functions, such as displacement mapping in textures which we see in a lot of new games. That alone is crazy optimization because it allows you to make flat surfaces seem 3D, cutting down on vertex operations(fast) at the increase of pixel operations(reeeeally fast).
They didn't need to do this to port some of the graphics processing from the CPU to GPU with Shader 2.0. If anything this is going to make new content look incredible and fast, with the old content being very much the same as it always was. And its going to make their current shader rendered objects(like PCs, NPCs, and shadows) look even better for less cost.
Why PCs and NPCs? Armor pieces can now be less complex geometrically, using
displacement mapping to give it more 3D detail.
Looking forward to seeing if their graphics programmers and artists are to the challenge tbh.