Make sure your hunters are bringing a Serpent or Hyena (Attack Speed buff), and a Wolf, Quilen, Devilsaur, or Water Strider (Crit buff). This isn't going to make or break you, but it's going to hep optimize your DPS. A Wind Serpent or Dragonhawk would be acceptable, but non-optimal. If they are using any other pet than one of those, they're wrong.
My guild did Normal Garrosh a long time ago, when we were struggling with DPS due to being undergeared. As a result, we used a strat that allowed us to focus more damage on Garrosh, especially in Phase 2, to push him before a 3rd Heart phase. It sounds like this might be helpful to you, and may also make Phase 3 go faster.
We used 2 healers and 1 tank. Solo tanking, especially with a Paladin, allows for massive Vengeance whoring, resulting in huge heals and absorbs, as well as hilarious damage from the solo tank if they know how to play. Doing this correctly basically gains you another full DPS and half a healer. Solo tanking, have the entire raid group go left and then right on the Split heart phase.
You also have very, very mobile DPS classes who do not suffer much from movement. I would highly recommend not killing Desecrated Weapons in Phase 2. These weapons have a little over 5 Million health on 10m Normal. My group achieved this by moving immediately to the right of Garrosh's throne with the ranged group (the tank follows, holding Garrosh and the melee group within DPS and healing range), and then moving just to the edge of the Desecrated Weapon to drop each subsequent one. Optional, you can have the ranged group run in and out of melee before each MC, and then back out to their position at the edge of the previous Desecrated Weapon after the MCs are dealt with.
Tank him in the clear middle of the room for Phase 3. We ignored the adds, let the tank pick them all up (though we had an Army), and focused down Garrosh and the MCs.
This is just an option for your group. It may not work for you like it did us, because skill levels of various players will differ in throughput and strategy execution.
Good luck finding something that works for you!