If you go by the numbers, Kimberly isn't actually all that dated, and it's been popular for several generations now. I think it's a modern classic.
I think it's very pretty. Kim is okay but I think it's nicer and a bit more distinctive to go by the full name. Kimmie/Kimmy is icky, and for some reason has a transvestite vibe to it; the Drag Race type.
You're entitled to your own opinions. You're not entitled to your own facts. -- Daniel Patrick Moynihan