You got me wrong in a few points. I'm of course aware of the fact, that dmg isn't identical.
When I'm comparing dmg on the tank or the raid, I put this into the big picture of healers available and currrent acitive problems, in the moment where the dmg occurs.
For example: If the tank takes 50% more dmg in 16man but you got 100% more healers free, to heal the tank, it will be more easier in most cases (assuming, that the tank won't be a two-hit through increased dmg).
Difficulty between sizes: 16 man is a little more difficult than 8 man do the damage going out, especially at end. Slight difference though between the two.
That's wrong. Your looking only at the numbers and totally forget two things: It's more difficult to heal the party, with only one healer, regardless of incoming dmg and the groundslam, which you are mentioning can be outranged bei more than 50% of the raid (if you assume 50% ranged dps and melee dps)
Stormcaller/Firebrand - Tank damage is nowhere near identical. In 8 man hard mode, you can ignore the Firebrand armor debuff with a minor cooldown
25k dmg isn't really easy.
16 man, depending on positioning of the shields, can make it difficult for the Stormcaller tank at the end of the Defensive Systems.
That doesn't really makes sense. What impact has shield positioning on the stormcaller tank? Run in circles and leave a trail of these rockets isn't really that hard.
If you get a DD right before Defensive systems in 8man, no biggie. Damage is minimal. Do that in 16, one person may die, possibly two.
That's wrong again. We never lost anyone due this example of yours. You simply ignore the fact, that you have more classes available for soaking, with different defensive cooldowns.
The dmg the cannons put out in 8man is minimal and can be ignored. Several guilds have ignored the cannons at the end, so no reason you cannot. In 16 man, they have to be dps'd down not once, but twice
First sentence is wrong. @2nd: We didn't even had a second spawn in 16 man. Is this the harder dps requirements you are talking about?
Kephess - Much more difficult on 16. 3 droids have tons of hps, and requires coordinated interrupts on all 3 before the damage comes out. I could swear the cast time is faster in 16 and requires quick reaction times (former enhance shaman, so no issue here).
You are right about this and I already mentioned it. We still didn't die without interrupting the first 2 droids in our first attempt in 16 man, because we didn't pay attention. The 3rd droid was already fully calibrated. To say 16 man is hard because of this phase is still far away from true.
Bomb carriers were easier to kill in 8 man versus 16 man. We only lost the bomb once in our attempts in 8 man, and several in 16 man when trying to get people acclimated to the encounter.
Maybe there is an issue with your players you don't bring to 8 man. Again, killing Carriers in 16 man was very easy compared to 8 man. Even with half of the raid didn't know the ecounter.
Everything else seems to be well balanced between the two, with a slight advantage in 8 man.
Completely ignoring everything I mentioned, gratz.
My guess is, that live 8man is much more harder than early PTS. Otherwise I don't know where you take your assumptions from.