Today, I had to enable python and perl USE flags globally in /etc/make.conf. I guess Gentoo changed the default setting for these flags. Personally I like having the kind of built-in tools and scripts that these provide, so I turned them on. Plus, enabling these flags avoided having to rebuild dozens of ebuilds (I have a lot of stuff installed).
I can understand why the Gentoo devs did it (most people don't need perl/python/ruby support embedded in Vim, for example), but I'm beginning to think there's no way for me to keep up with changes, or if there is, I totally missed it, so everytime this changes I'll be looking at Bugzilla and the Forums. Maybe there's a way I can track these kind of USE flag changes on my own system, in a more obvious way then the output from eix-sync. I'll have to look into it.