when more and more people that buy their games, the more revenue they get. The larger the amount of money the company has, the larger the amount of tools they have at their disposal to create a better game than the last. Hype is a very powerful sales tool, and it worked quite well for GTAIV. It pissed some people off, but rockstar is now richer for it.
While that makes since, You also have to consider that getting all those people hyped up for a game they found dissapointing is not going to help then in the long run when GTAV comes out and all these people say "F*** it GTA IV sucked why wont this one?" yah know? That is if that's what you meant by "It pissed some people off"
On topic: I like how the gangs blend in,I never really thought of them as gangs until reading this but now it totally makes since, I love it when I'm randomly killing pedestrians and some gang member is like "hell naw" and starts shooting at me from like 100 yard away, it's fun!