I'm a bit confused here.

You might be able to get enkindle up in 5 seconds, but why would you need to? Going by your reasoning that the tank has no aggro, wouldn't that immediately snap aggro to your pet?

Also where are you pulling these GCD saving numbers from? You never save GCDs, doing anything. In fact by using your stuff immediately you actually push back your DoT application by at least 2.5 seconds, which is a big nono.

Furthermore this is the opening rotation. You won't see a rotation like this again until 60 seconds later, when swiftcast (if you choose to use it) and contagion are back up.

Because contagion increases the duration of your spells, its actually a time of relaxation right as you finish miasma II...you get ~20 seconds of "free" time where all you need to do is spam ruin.

Just because we're ranged doesn't mean we can't be in melee...and thats the rub right there, why melee get screwed so much. Its not that they have to dodge more than ranged. Its because they can't dps at range, while we can dps in melee, giving us freedom of movement while they're chained to the boss.

I'm not advocating the necessity of staying in melee all the time, but frankly many bosses don't move much, and don't fart in your direction, so staying in melee is as easy or easier than going ranged, and running in (or staying in) to miasma or melee isn't all that hard.