Optical ZDefocus?

Something that would be a big draw for people wanting to use Blender as a compositing tool would be a very good Optical Defocus tool.

Coming in as a Nuke compositor the way Nuke's ZDefocus handles edges in depth maps hasn't been replicated anywhere else. No system for this is perfect but if Blender would be able to replicate somehow Nuke's ZDefocus node that would be amazing.

On top of this in Nuke there is the PixelFudger tool set which has a node called pxf_ZDefocus which allows you to emulate physically accurate lens data which drives the defocus.

I've created my own node group which does this but the issue is that with the current Defocus node the edges are always a bit broken. I can mitigate it in ways but it's never amazing and isn't comparable to Nuke's system.

It's quite a setup:

It achieves the right outcome. Sharp edges end up slightly blurry and there is a hard line in edges that should be soft:

Nuke output for comparison:

It's very nitpicky and there are ways to mitigate this further which would result in more work. But if Blender could improve the current system and somehow replicate what Nuke's ZDefocus node is somehow able to achieve it would be a big leap forward!