This is not what I call a downgrade

[Preypacer]

It does look fantastic, though the sheer volume of shadows on the ground from trees I fear will look like a giant mess with my shadow settings turned down to minimum like they usually are (for performance rather than detail).

They're upgrading to a deferred renderer in 2.0 which, if you've ever seen one in action, are amazingly fast and efficient. Normally, all the shadowmaps/objects on the screen are updated every frame. With deferred rendering, only the parts that change are updated.

Here's a video that does a good job of explaining and demonstrating it.

Also, though I don't know if SE will offer this option, but a lot of games will offer a lower setting where shadow-maps are used in lieu of dynamic shadows. You lose the nice effect of shadows moving on the ground and across objects, etc.. but you at least don't get the "blob" effect you're concerned about. Again, I'm not sure if SE will be doing that or not, but it's possible.