People who chastise GTA IV for not being as ridiculous and over the top as the older games, to me, are completely missing the point. Rockstar purposefully de-constructed the theme of the previous generation. GTA III era games all acted like it was awesome to be a gangster, sure there were setbacks, but you could always overcome it and kill everyone. They were also, looking back, very juvenile. When IV came around, the series went the other way and showed how shit the life can be, how much it messes you and those around you up. It wasn't trying to be the previous generation, it wasn't trying to outdo San Andreas in the "zomg jetpacks and fighter planes and naked BASE jumping" stakes, it eschewed all that in favour of a more mature and frankly amazing narrative. Hell, it's probably only called GTA because it's basic gameplay is the same, "kill people, shoot things, steal cars" which has been there since the first game.
I for one loved it and wish people would stop ragging on it for not being San Andreas II. Sure, it's not perfect, but it's still one of the best games ever made. If you want more San Andreas...go fucking play San Andreas (or Just Cause 2).