While this is a very welcomed change, i feel the split diff view could do a much better job on some cases.

For instance, this is how GitHub renders a commit that adds a wrapper HTML element (and indents all its contents) and changes a class name: http://i.imgur.com/4Lcozgz.png. Not so good. Contrast that with how IDEA renders the same diff: http://i.imgur.com/RGf8psr.png. It makes it obvious where the wrapper tags where added, and which class name changed (which is completely lost within the green glob of the GH diff).

Now, the whitespace-agnostic view on GH (adding ?w=0 to the diff URL) is much better: http://i.imgur.com/AKNn1fW.png. It looks very similar to the IDEA version: http://i.imgur.com/NpDsYBB.png. I wish GH remembered the ?w=0 preference just as it remembers to use the split diff.