That sort of code and API sanity (avoid giant rewrites, keep the API stable) is far, far better these days than back then.
In OSS one can only do so much. The libgnomeui/GnomeMDI stuff took a long time to reach consensus. So for example, in January 2001 I was apparently telling people not to use it: https://mail.gnome.org/archives/gnome-devel-list/2001-Jan...
But, someone else would have told you to use it at that time.
It just depended on who you asked. There wasn't a dictator to decide.