The fact that you state that as if you're actually proving a point just shows how little you know. How many non-CD, non-DoT spells do we cast? Mind Flay? So you'll increase the DPS of our worst spell by 1% whenever you go for haste in between breakpoints? Brilliant, I'll start re-gemming right away.
Do you know the DPS % increase for 1% of crit or mastery for comparison? Or are you only focusing on haste because it's what all the cool sim kids are doing? Just FYI, 1% crit is also a 1% DPS increase... for ALL spells, and you don't need to worry about reaching breakpoints to see that increase.
1% mastery is also at least a 1% DPS gain for most of our spells, plus you get more instant Mind Spikes and Mind Blasts because of the additional SW:P and VT ticks. Again, no breakpoints to worry about before you start seeing the benefits. Every single point is worthwhile no matter how much you currently have.
---------- Post added 2012-11-07 at 03:52 PM ----------
It may not be rocket science, but it definitely isn't that simple either. Each 1% of haste does not grant an additional tick to all of your DoTs. If you read the rest of this thread, you'd notice that you gain zero DoT ticks between ~2020 haste and ~8060 haste. That's a pretty significant gap considering the amount of reforging and gemming that needs to be done to hit the latter number in average gear right now.
In the thread you linked, the 250PP value seems to be derived from a 1% difference between sim results. Maybe I'm being overly cautious, but I think it's a little naive to assume a sim created by non-Blizzard programmers with no access to the WoW source has a <1% margin of error.