GTA is definitely not hanging on by a thread, I still think it's the most successful video game franchise out there, and I've met tons of people that agree with me.
We get hurricanes up here in the NE every once in a while. If they have seasons then I think it would be o.k. to implement it but they probably won't do it. Something that they seriously need to implement is snow. If they don't it really won't feel like NY that much.
Rockstar has released a few new downloads that include desktop wallpapers, screensavers, avatars, and buddy icons. You can find them here. Rockstar has also released a new poster for GTA IV which you can order for $15.00. This poster just shows the generic GTA IV logo with the "RP" rating and red text that says "COMING SOON". You can order that here.
As far as I know the PS3 and Xbox 360 support custom tracks, and I'm 100% positive on the 360 part. So, chances are, you will most likely be able to create your own radio station.