BLM Single Target Rotation and Mob Movement

[Synovius]

1) Why do I see that its recommended to start single target DPS With Blizz 3 - Thun 2? I get the thunder but why don't you start with Thun 2 or Fire 3 first? I tried the above and it seemed slower to start ramping up.

2) How do you deal with when you start casting but a mob runs by you and now your not facing the correct way and the game doesn't auto correct you because you faced the mob already when you first started to cast?

You start with Blizzard III for three reasons:

1) It makes your subsequent Thunder II and Fire III free as you'll get a tick of mana as you're casting Fire III
2) It allows an extra second or two for the tank to establish threat before starting in on the heavy DPS portion of our rotation
3) The rotation for BLM hinges on maximizing Fire I spam. If every turn through your rotation is going to result in, say, five Fire I's before you have to cast Blizzard III, why would you want to start your rotation differently such that you only are able to fit 4 Fire I in instead? Not only does this not make sense but often times the opening to a fight is a crucial time to maximize DPS before many of the fight's mechanics (especially movement-based mechanics) kick in.

As to dealing with moving mobs, simply rotate your camera with the mob such that you're facing the mob when your cast bar is roughly 80% finished. Personally, I would never rely on the "face to cast" option built into the game. It's bad practice for many, many reasons. You should manage your own direction as needed and not rely on the game to automagically face you in the direction of what you're attacking. If you want a specific example of why using this feature is bad for BLM, consider Turn 7 and the "voice" mechanic wherein once the debuff falls off of you, you shoot a cone in front of you that petrifies anyone caught in it. If you have the face to cast feature turned on, expect to voice the raid quite a bit as you try and fit one more cast in before the debuff falls off.