Because I can, I'll pick apart Dragoon, and why both your suggested openers are significant DPS losses.

- Not only does the potion miss Chaos Thrust, a massive loss on its own, it won't even last long enough when you reach your second Full Thrust. Potions should either be used pre-pull at one second or following True Thrust; with Dragon Sight being used pre-pull instead.
- Why would delay Dragon Sight and Lance Charge by six and seven GCDs, respectively? That is an enormous loss that will inevitably cost you a use of both later into the fight. They should only ever be delayed in optimized settings where you know doing so won't cost you a usage.
- You never, ever lead with Jumps. Not only do they loss the benefits of your buffs, it serves you no purpose going into LotD early. Speaking of which...
- Don't go into LotD early unless a fight demands it. E3S comes to mind, where you'll lose Nastronds due to Maelstorm. Otherwise, going in early will cause your Nastronds to miss raid buffs further down the road.
- Why is BotD randomly used during the opening rotation? You delay Hi-Jump/Dragonfire Dive to press a button which is completely useless as you'll have full gauge because you literally just hit Fang and Wheeling.

That last point is probably the best demonstration of how little you understand about the jobs you're attempting to offer optimization on.