The OP is terribly uninformed.
Strafir, you can't win an argument by being constantly hostile and claiming everyone else to be an idiot.
Simple maths.
15% damage increase, 20% uptime. That equals 3% damage increase. I'm not going to go search WoL to find the true highest DPS, but it seems like the respectable average of the lowest dps on the screenshots of world firsts is approximately 25,000 dps. 10 percent of that is 2,500 dps and 1 percent is 250 dps. 3% would equal 750 dps.
The highest I remember seeing on those world first screenshots was a Death Knight with around 35,000 dps. More simple maths. 10% of that is 3,500 dps, 1% would be 350 dps. 3% would then be 1050 dps.
There you have it. On those world first kills, the difference of giving Tricks to the to the lowest DPS and giving it to the highest DPS (which, btw, the Rogues were in the higher range anyway), would be a whopping 300 dps.
For simplicity, lets find the average DPS of each raider by simply adding 25,000 and 35,000 and dividing by 2. Hell, you don't even need a calculator. The average would be about 30,000. Let's multiple that number by 18 (25 raiders minus 5 healers and 2 tanks). That's 540,000 raid DPS (roughly, not counting the tanks).
Yes, a 300 DPS difference from a group that's already dealing 540,000 raid DPS.
That doesn't even register at a hundredth of a percent of your raid's DPS.
If your group is playing right, a 300 dps difference is never going to make or break an encounter. At the current numbers, it won't even come remotely close.
Math is hard.