I'm sure most of you probably already know everything you need to in order to execute the mechanic properly, but to avoid a few extra wipes I'll try to make things clear. I've done my best to research and provide the most accurate explanations. If at any time you are able to identify any errors, I will correct them.
Here is a small Youtube video that explains Malice
(Although the main video is about the Ra'Sha dagger which is useless now).
http://youtu.be/i3fIKvSegRM?t=1m18s
Stolen from battle.net (but edited):
"The "Iron Star" that spawns only comes during periods of bombardment and then only at set points does a check occur to see if there is a clump of people. If there is a clump (3 people) then he will fire an iron star for each clump detected per clump check. These iron stars fixate on the closest person to them. They must be kited and brought to Garrosh just as he casts his big death spell, which he casts at 100 energy, that will spawn adds. On impact, the star will interrupt Garrosh's cast. The goal is to hit him with an iron star exactly as he starts to cast. If the iron star hits your kiter, your kiter will die. Also, regardless of who the iron star hits, it will do raid-wide damage. Ideally, you only want to have one iron star spawn in phase 4, and that's during your first bombardment. However, if your P4 is long and you need to interrupt Garrosh a second time, then you'll want a second iron star. The goal is to kill him before this happens however.
The person targeted with Malice will have a purple ring around him/her. Every 2 seconds Malice will apply a stacking debuff which lasts for two seconds to a certain number of people (2 people) inside the ring. If there aren't enough people for Malice to hit, it will give Garrosh energy, which will cause him to do his big cast sooner (Manifest Rage - Many Adds). Ideally, you only want someone to ever get 1 stack of this debuff, although for Malice #4 we had designated people take multiple stacks because of the timing of that Malice with bombardment and not wanting an iron star.
Bombardment is just a periodic mechanic where a ship from offshore will shoot stuff at the ground where your raid needs to dodge both the impact of the shots and the fire left after. It will require you to move the boss each time to a safe spot."