That's kind of the way all the sights are. I too prefer the options with finer dots/crosses in the center.
I think there's an argument to be made that having some kind of bum options makes the better ones you unlock later worth pursuing. If they were all more or less the same, there wouldn't be much of a sense of progression.
Personally, I'd be cool with everyone just having everything unlocked off the hop and the progression being cosmetic stuff/player card swag. That'd be pretty A-typical for a modern Battlefield though.
I'd guess that the sights in game are a pretty faithful recreation of actual sight. Their weapon models all seem bang on (excluding the couple that are totally made up). I'd be surprised to learn otherwise.
