T dog, your ideas are quite good however im assuming youve played gta:san andreas if oyu do 12 fire fighter missions you never be on fire hence no need for the fire suit.
I like the idea of pedestrians in the woods hiking, i would like to see myself a big snow park where people ski. Also it would be good if you could have an avalanche but thats probably too much.
The money system i like however it would be good if you could deposit money and every month interest comes in (more money equals more interest) however you would have to pay about $1000 or £1000 tax each 6 months or every year.
I myself would like to see these things in gta4-
1. Different cars (The car sentinel is in gta 3, vice city and san andreas)
2. Normal time not 1 minute per second
3. Have about 10 islands but some islands dont connect with each other via bridge. You would have to use planes or boats.
4. Be albe to snap twigs and branches and use them as weapons.
5. Design own tags and can use them anywhere though have a rule each tag has to be say 100 yards away from another. This way you wont get tags everywhere.
6. Dont know this would happen but it would be good if you could startthe game as a boy and gradually grow older and older.
7. Be able to pop bike wheels
8. Be able to enter every house though if you do you will get the police after you.
9. Police have different cars i.e one police man has a flash and another an emperor.
10. Police cars have to hold 1,2,3 or 4 policemen instead of the always one