I really wish Hardline was a green perk. It doesn't have enough potential to merit being a red one when you could have something better like Stopping Power or Cold-blooded.
What's REALLY bad are all four of the death streaks, which are all pretty useless in my opinion. Copycat is purely useless, Painkiller just urges you to be suicidal with the ridiculous 10 seconds of extra health that either goes unused or ends up killing you instead in your failed kamikaze effort to actually put it to use, Martydom never actually kills anyone ever, and Final Stand is really not much different from Last Stand, both of which are useless if you're killed via knifing or explosions, which there are a LOT of.
To me, MW2 wouldn't get any less realistic if you started adding in laser guns, dragons, magical spells and time machines. Its already that ridiculous. XD