Have the changes in Cataclysm been overwhelming for you. None may have been more than those of the classes, the Hunter in particular. In receiving three new abilities I can assure you that you will see a much more effective character. The Hunter always seemed to be so under utilized in the previous versions of Warcraft. I would assume the Hunter will be more of an ally on raids and PvP runs now.
Let’s start off with the new abilities of the Hunter. At level 81 you get what is known as Cobra Shot, this causes Nature damage instead of just pure Physical damage. If you combine this with the talents of the Beast Mastery tree, you are the go to guy in just about any situation. The Hunter would make an ideal character in a fight against a heavily armored target. It will share a cool down with a steady shot.
At level 83 Hunters will get Trap Launcher, this will allow you to shoot any one of your traps up to 40 yards away in a similar fashion to the Freezing Arrow Trap which will be removed. Finally at level 85, Hunters will be given Camouflage, which effectively hides them and stops them from taking any ranged damage.
those are just some of the smaller changes to the Hunter. For example, mana is no longer used, instead you have to build up focus which is similar to building Rage. In order to use Steady or Cobra Shot you have to have enough focus available. To me this was one of those really big changes that you need to get use to.
There was a time when a Hunter had to carry his ammo with him at all times in the form of either a quiver or an ammo pouch. As time went on these were taken away and the Hunter could carry his ammo in a regular bag. This meant that the Hunter could carry ore ammo than ever before. now once again this has all changed, there is no need to carry any ammo. All of your guns, crossbows and bows will do damage without the ammo being carried.
As a a Hunter you will start with a level one pet and have the ability to carry up to three pets at any given time. You can swap out any of your pets, however you can still only carry one at a time assuming you are not in combat. If you want to swap out your pet you will still need to visit the stable master to do this. So as you can see the changes for the Hunter have improved him greatly since WotLK.