I must admit, after playing the original Postal after I got it from Desura (on Linux of course) it has actually grown on me. The controls are a little hard to wrap your head around, but they do provide for a rather anxious gameplay experience (in a good way) as you are never really that sure where you are aiming and what is behind you. It adds to the games dark ambience.
That being said, going the opposite route and allowing for a lot more control over the character will make the gunplay and the violence itself a lot more satisfying. I mean, what made Postal 2 (and especially Apocalypse Weekend) so fun was the ability to do almost anything with the game-world and watching the physics in action as you shot, hack, slashed, burned, and pissed your way through the opposition.
Both methods have their merits, and the latter will certainly show off the technology a lot better. But I must admit that Postal 1 is not as much of a trouble masterpiece as the first level made it feel for me initially.