It would be nice if a bash-completion USE flag were available that would append the following to /etc/bash/bashrc: [[ -f /etc/profile.d/bash-completion.sh ]] && source /etc/profile.d/bash-completion.sh That way when the bash-completion USE flag is turned on globally, the new features will immediately become obvious. I know that it is somewhat unusual to use a USE flag for a configuration setting, but net-misc/dhcpcd does something similar with its zeroconf USE flag.
Nevermind. Turning this on is more involved than I thought it would be, so the initial thinking that caused me to open this might not be correct. I will revisit this idea when I have the feature enabled to see how useful my original suggestion really would be.