The angle that the cable makes relative to the clutch arm makes the pull easier. If you look at a stock warrior clutch cable and arm (in the engaged position, meaning the clutch lever is not pulled), the cable will make an acute angle (<90 degrees) with the clutch arm. This makes the pull difficult, because you are putting the cable at a disadvantage mechanically. Now take a look at the cable on the raptor 350 set-up. This angle will be greater than or equal to 90 degrees, which gives the cable a mechanical advantage over the stock warrior setup.
The reason the warrior setup was designed poorly is because the header was in the way of were the cable bracket needed to be in order to run the correct geometry. (I assume this was issue).