Rugby 2004 is shit, yes, but its player stats are absolutely horrible. Rugby League's player stats aren't at fault for being wrong, just the game balance. Fast players like Clarke, Merritt and (unfortunately) Milford do well in the game because of their speed. I'm using Parra and while I find Nathan Hindmarsh horribly ineffective (his offloading and break tackle are criminally low), Jamie Lyon is my top try scorer in most seasons (especially now on legend) because he breaks the first tackle, and is reasonably quick. Petersen is a machine though, you are right, his break tackle is huge.
Playing on legend I've found the top players really come to the fore, especially when playing against them. The best forwards and backs are almost impossible to stop, and when the defense is tighter the fast backs have less of an advantage.
I can accept that you've come up with some good reasons for disliking the game, I've had mates who also haven't liked it and even returned it because they can't stand the niggling faults, but I feel I've persisted with the game and find it great fun to play despite the faults and bugs, especially on the tougher difficulty levels where a lot of the AI defensive faults are remedied and it takes some great plays to score points. I'm hoping the game improves as it goes on too,.
By the way, playing against Brad Fittler on league god, you'll wish you had a damn gun to stop the bloke, he breaks that many damn tackles. Don't get me started on Utai and Tallis, either. One thing the top difficulties do is make the top break tackle and agility players far more dangerous, for some reason the lesser players who may break a lot of tackles on seasoned mode stay about the same, while the good players come into their own.
I agree with you, the stats aren't perfect, but they certainly aren't terrible. I think the game balance is more at fault than the stats, and I also think that using official stats from NRL stats has hurt the game a little since basing the game on pure numbers discounts how good some players are. Sure Jamie Lyon doesn't offload that many balls compared to the NRL's top offloader stats, but in comparison to how many touches he gets he's one of the best going around. That doesn't get taken into account, and that's why I think the stats need to be worked on. They certainly aren't the worst ever though.
New Zealand are definitely overrated though, in saying that. Some bias crept in there.