There's also a historical angle here that's important to inspect - Git was designed to specifically be content agnostic. There are some predecessors in the SCM space (like VSS) that are specifically language aware and allow the checking out of line ranges (pinning them so that no one else will make a conflicting change specifically) and even entire functions - these systems can cause a lot of grief while failing to protect the logic they're specifically trying to protect. As the warts on SVN got more and more visible I think the general assumption was that the replacement SCM would come out of this code aware space - but it didn't and in retrospect we all dodged a huge bullet when that happened.

I absolutely adore tooling around git that makes diffs more visible - one thing I absolutely gush over is anything that can detect and highlight function reordering... however, the core process of merging and rebasing and all that jazz - I don't think we're going to find anything automated that I'll ever trust when I'm not working on a ridiculously clean codebase - minor changes can have echo effects and when two people are coding in the same general area they need to be aware of what the other person is trying to do.