Nami's ult should ping who's in range when you ping it
Not for my own info, but for my teammates,
It was a good addition for the likes of Jhin's ult, Lux's ult, etc. and adding it to Nami's would be pretty useful too as I, personally, mainly use her ult to engage teamfights. Having the in-range ping would just strengthen that communication to my team.
Just a thought! I'm sure there's some other abilities that would benefit from this too :)