The Marksmanship Sniper rotation follows a 4 GCD cycle:
A - F - X - X
- The heart of the rotation is F. F is the ability Followthrough, which has a 6 second cooldown, and must be activated by using another ability first. Following this pattern means Followthrough is always available right when it comes off cooldown.
- A is the ability which activates Followthrough:
- Ambush with proc. The proc reduces the cast time to 1 GCD. Ambush has a 15s cooldown.
- Snipe. A basic ability that costs Focus
- X-X has two possibilities:
- One 2-GCD ability:
- Series of Shots. Has a 15s cooldown.
- Orbital Strike. Technically an AoE ability, but does really good damage and costs a lot of focus. 45s cooldown.
- Two 1-GCD abilities. Choose from the following list:
- Takedown. Execute ability only available at low health.
- Corrosive Dart. Damage-over-Time.
- Explosive Probe. 30s cooldown.
- Scatter shot. Puts an armor reduction debuff on the boss.
- Rifle Shot. The basic auto-attack that does not cost focus.
It's a complicated rotation, but you can see that is is heavily structured. It's not just a priority list.
The other wrinkle is that a sniper must manage focus, and focus regenerates faster the more you have of it. So you do have to manage your focus a bit. For the most part, I find it's not an issue except when you use Orbital Strike.
So that's 10 abilities that get worked into the regular rotation. There's also 3 offensive cooldowns, about 5 defensive cooldowns, and an interrupt and an incapacitate which is sometimes used.
The Old Republic really has issues with ability bloat.
Now, you can simplify this a fair bit. Drop Explosive Probe and Corrosive Dart and don't bother with Orbital Strike for single-target. That brings it down to 7 abilities for a fairly minor dps loss, and pretty much takes energy management off the table. It also allows you to stay out at a greater distance, as all the remaining abilities have a slightly longer range.
Now is it a good idea to have rotations this complicated? Honestly, I rather think that this is is too complex. I generally prefer rotations with about 5 abilities. One of the other points to note is that The Old Republic doesn't have an auto-attack, so you have to fill every empty GCD with Rifle Shot. There's no such thing as a free GCD for you to do something else.
But then this is balanced by not being quite as strict with performance requirements as heroic raiding in WoW is. I would say that The Old Republic difficulty tops out in mid-heroic WoW, and has nothing like the killer end bosses (Lich King, Ragnaros, etc.)
What is your ideal rotation? Do you prefer structure, or a strict priority list? How many abilities do you want? Do you want to watch timers, to keep up debuffs? How much free space should there be? Do you want to keep track of a resource, or just go off cooldowns? What class in what game would you say has the best rotation?
Or do you just want 1-button Cataclysm arcane mage or Burning Crusade warlock spam?