I actually enquired as best I could as to why so many little (almost basic) things had been taken out of GTA4. The response I got was quite surprising, but made sense; they were rushed towards the end. It covered why the Hunter (Apache Helicopter), Sparrow (m*a*s*h-style helicopter) and Rhino (Tank) didn't make the final code. I hate to tease, but the Hunter was amazing in the Alpha back in October, as long as you didn't fire the missiles...
I too miss the extra things San Andreas added (not all of it, but definitely the truck trailers, and the airport tugs with their baggage trailers. I'm sure all them features will be back in future iterations, I just hope they don't forget the tug when they do. I'd like to tow a barge!
Talking of the tug (and other boats), I've got to say the horns are amazing. I wish shipsim had horns that good. I also noticed that on the twin-screw speedboats, each prop turns in the correct direction (unlike shipsims). Not being picky, there just 2 things I'd like to see fixed in a patch/2009.
Also, did anyone here get their key?! I don't qualify for one through the competition, but I have some other things anyway. I did finish the game 100% though by May 2nd...