I already noticed on a few maps that in the scoreboard during actual gameplay it highlights your friends on the scoreboard if they happen to be one of the ones that are already visible. It got me thinking that it might be nice for competing with your friends if the scoreboard showed their scores even outside the top 40. I know there's already the special case of showing your own best score, so there's already help towards implementing it. Of course, there's some other issues. If you have a lot of friends it could be pretty crowded, so perhaps limit it to the top X friends, and/or ones with a lower score than your highest. It would perhaps encourage people to spam friend the top players, but as far as I know there's no real way to tell if someone has friended you unless you stumble upon their profile and therefore no real annoyance or actual harm to being spammed with one-way friendships. It may or may not need to be an option, if quite a few people think they'd want it the old way. It seems like a practical implementation with my novice programming knowledge, but you never can tell sometimes.
The other idea is a friend score board toggle the same way there's a local and global toggle, but that sounds like it'd be tougher to implement.
The other idea is a friend score board toggle the same way there's a local and global toggle, but that sounds like it'd be tougher to implement.