"Modern Linux distributions are in the process of deprecating ifconfig and route..."
Deliberately removing something means you don't have to maintain it any more and can spend your time improving the better tool rather than bug-fixing the legacy one.
I understand improving, but it wouldn't take much effort to make it user friendly, by wrapping over the ifconfig command for at least the reporting functionality. It could still call ip underneath.
There are ways to handle it that make it backwards compatible and user friendly without only a little extra effort. It's not a sexy task, so who cares about usability.
See: http://en.wikipedia.org/wiki/Ifconfig#Current_status
"Modern Linux distributions are in the process of deprecating ifconfig and route..."
Deliberately removing something means you don't have to maintain it any more and can spend your time improving the better tool rather than bug-fixing the legacy one.