Preparation has always been our most controversial ability. From the early episodes of The World of Roguecraft, to the chart-topping AR/Prep days of BC, to our recent Prep vs Step conundrum, Preparation has always been the focal point of rogue cooldown discussion. Many rogues have advocated removing Preparation altogether and adjusting our cooldowns to be potent without it. Several other classes don't see the ability as a fair technique, lending itself to our image as a cooldown-reliant class.
Blizzard clearly has other thoughts on the matter, as the ability will become baseline and available to all rogues at level 68 in the upcoming 5.2 patch. If I was making a list of rogue talents that might become baseline abilities, Preparation would've been all the way at the bottom. Many vocal rogues have been asking for Shadowstep to be added to every rogue's repertoire to resolve the Prep vs Step debate, but I don't think anyone saw the reverse happening. The decision to baseline Preparation is a clear buff for rogues everywhere.