I used to think it was one of the worst entries. However, I played it more recently, and I think I've changed my mind. It still has very little to do gameplay wise(drive here, shoot that), but I've done a complete 180 on the physics, and driving mechanics.
Everything in GTA 4 has a real weight to it, which leads to more unpredictable results, when messing around in the world. The driving can be a pain in the ass, however, there is a learning curve involved and a sense of accomplishment when you are able to pull off some crazy driving moves. You really have to learn how to control the car in a more sim like manner, unlike in GTA V, which feels a lot more arcade like. There's always a sense of danger behind the wheel in GTA4, like one bad turn can send you cartwheeling down the freeway. It helps routine drives around the map from getting stale. It's a double edged sword however, because fucking up a simple drive from point A to B can be frustrating, especially when you consider that GTA4 had no mission checkpoints. Yeah, fuck up the escape at the end of "Three Leaf Clover"? Back to the beginning you go.
Anyways, here's one of the few videos I checked out a little while ago, that made me give GTA 4 another chance. Glad I did.