One of the things happening to hunters in the 4.03a patch is that all of our special attacks are being normalized with respect to weapon speed. Let us reflect, for a moment, on the oddity of that sentence. What does it mean to have an attack normalized? What does weapon speed have to do with anything? Wasn't that something only rogues and stuff worried about?
To explain what's going on here, let's first take a look at two different imaginary bows. [Humbert's Mighty Twang-Stick] as compared to [Wesley's Elegant Willow]. Humbert's is a 100 DPS weapon with a 1.0 speed and Wesley's is a 100 DPS weapon with a 2.0 speed. That is: they're both 100 DPS weapons, but Humbert's is twice as fast as Wesley's, firing once a second instead of once every two seconds. It's pretty obvious that Humbert's is going to have to hit for 100 damage every shot to do 100 DPS, while Wesley's is going to have to hit for 200 damage every shot to do the same thing.
So here's the issue: the formulae for most damaging abilities for a hunter look like this:
Platypus Shot attacks the target, doing ([weapon damage] + [N% x Ranged Attack Power]) nature damage and dazing the target by forcing it to consider the inexplicable reality that a creature such as the platypus exists.
What that little formula in parentheses means is that the game figures out how much damage a white attack would be, then adds a number to that by multiplying your RAP by some percentage. If you think back to Humbert's and Wesley's respective bows, you'll realize that the weapon damage the game will calculate for Wesley's is always going to be higher than the damage it calculates for Humbert's because Wesley's is a slower weapon. If you had two otherwise identical hunters shooting at a target dummy and using only Platypus Shot, the one with Wesley's will do more damage because his platypi are envenoming harder.
Or at least, that's how it used to be. With patch 4.03a, hunter weapon speed will be normalized when the game is calculating our special shots. What this means is that Blizzard have picked a speed (hopefully 3.0 or slower), and every time a special shot needs that "weapon damage" value, the game will figure out what weapon damage the weapon would need to pull its stated DPS at that normalized speed.
To go back to our example bows, imagine the game normalized hunter weapons to a 2.0 speed. If this were to happen, the two identical hunters will do identical damage. This is because every time our hunter with Humbert's fires his Platypus Shot, the game will go "if this bow were a 2.0 speed weapon, it would need to hit for 200 damage to do 100 DPS, so that's what I'll use for weapon damage for this shot."
This is overall a positive change because it makes the game a little more intuitive. Without normalization, hunters were using the item-level 264 Wrathful PvP bow over item-level 277 heroic Zod's, even though the DPS rating on Zod's was higher. They were doing this because Zod's was such a fast weapon that the PvP bow's special attacks were still hitting harder than Zod's were. With normalization, the answer to "which weapon should I use in Cataclysm?" is almost certainly going to be "the one with the higher DPS rating."