Next, if the Arrows can fire faster and faster the more APS you get, wouldn't that mean that the weapon damage changes?
sorry, let me clarify, I don't mean weapon DPS, I meant damage.
the tool tip is actually trying to tell us, as simply as possible, that rapid fire is 228% weapon so we can easily compare with your other skills. The nuances of how it works it is no different than any other skill so let me re- tooltip
it could say this;
Cost: 20 Hatred initially, and 1.66 per arrow
Fires arrows that produce 38% weapon damage as physical, at 6 times your rate.
I'd also like to point out that no matter what, tapping the mouse/key will produce at minimum 0.5 seconds of arrows... no matter how much you try to waste hatred. so you will never spend only 20.. it will be about 25 minimum cause 2-4 arrows will fly out
let me be verbose with an example since math translates best
weapon: 48-49 damage
ring: 1-2 damage
[(weapon + rings)*.5 * dex] = 100 damage
* 1.00 aps = 100 DPS
each arrow is avg 38 damage because
(weapon + source)*.5 *.38
* dex = 38
you fire 1.00aps * 6 arrows a second
thats 6 arrows so = 228 dps (@1.66 hate per arrow + initial cost of 20)
double the APS to 2.00 and the char screen will now say 200 dps, but we know that your (weapon+sources)*.5 * dex = still 100 damage
each arrows is still 38, but you now fire 2.00aps * 6 arrows a second = 12 arrows, so 456 dps
Your hatred spend rate has also doubled, so RF has not gotten a better hatred/damage return, just a better damage/sec the same as any ability benefits from more APS