So why don't they make a fun game that isn't about random killing spree missions? If GTA4 isn't mainly about killing I apologize.
You could argue that about any shooting game. Isn't Call of Duty 4 just random shooting missions, isn't Smash Brothers Brawl just random fighting? With GTA4 (and arguing and defending something on the internet is utterly pointless, but....) yes you do kill people, but the character development is what makes it addicting, and the story itself is pretty fleshed out. It shares a few RPG elements, but I guess you could say that about every open world game. It's a fun game because the mechanics work well, and sometimes yes, you just need a good "go randomly kill people" game, if you want to describe it that way.
I love the game, and I guess much like you all probably think I'm missing out by not playing [insert japan-only RPG here], I think you're missing out by not at least trying this game.