The Gentoo news post is not about having /bin and /usr/bin as separate directories, which continues to work well to this day (I should know, since that’s the setup I have). That configuration is still supported.

The cited post is about having /bin and /usr on separate partitions without using an iniramfs, which is no longer guaranteed to work and had already been awfully iffy for a while before January. Basically, Gentoo is no longer jumping through hoops to make sure that certain files land outside /usr, because it was an awful lot of work to support a very rare configuration.