I have in the past successfully persuaded Apple to :-
- Add support to macOS X aka OS X aka macOS to be able to use WPAD i.e. Web Proxy Auto Discovery which Apple calls 'Auto Proxy Discovery'
- and add support to their DHCP server for DHCP option codes as used by VoIP handsets and other network equipment
I also wrote myself a GUI tool to make it far easier for people to generate the encoded values Apple required for DHCP option codes in their bootpd.plist config file. See http://jelockwood.blogspot.com/2013/06/dhcp-server-on-os-x-server.html
This tool still works by the way.
However the one thing I did not succeed in persuading Apple to do was adding an IPv6 capable DHCP server. Apple's DHCP server is based on an extremely modified bootpd package which never was able to support IPv6.
With the recent(ish) announcement from Apple of yet more services going to be removed from their Server.app including the DHCP server it is clear that IPv6 is never going to be added. It also means my tool will no longer have a purpose.