They should have a radio station for:
1. Hip-hop/rap (Playback, Liberty Jam, Radio LS)
2. Techno/old school rap (Wildstyle, Rise)
3. Oldies (K-DST)
4. 80's (Flashback on III, Wave)
5. Jazz, preferable smooth jazz (somewhat like Master Sounds, but more contemporary)
6. Classical (Double Clef)
7. Asian music (Somewhat like Radio Del Mundo, but more far-eastern Chinese and Japanese music and less Middle-Eastern/South Asian)
8. Latin Music (Esparanto)
9. Soul/Funk/Disco (Bounce, Fever, Flashback on LCS)
10. News, Talk and Sports. (The news broadcasted will change as you progress through the game and commit big crimes from missions like it does on SA)
With more disk space and seeing how they probably won't use a large land like they did in SA, they could try to add 10 radio stations!