BRD has a much higher skill ceiling in terms of optimization than MCH does. BRD’s DPS optimization is all about making the most they can out of their DoT damage and procs; there is a section in the current BRD guide (that is super long) that gives potency increase values for each raid buff (Litany, Chain, Trick Attack, Spear, Balance, etc.), and how much a BRD gains and loses by choosing to double-snapshot each buff with Iron Jaws. The guide even explains that it is actually a gain to triple weave a Bloodletter > Empyreal Arrow > Bloodletter during Mage’s Ballad and clip your GCD as opposed to doing BL > EA > HS > BL.
BRD isn’t as heavily reliant on ping as MCH (though high ping can cause double weaving problems, and in Army’s at 4 stacks of Repertoire, you end up clipping if you double weave and it just cannot be helped even at a low ping), but the skill ceiling for BRD is still incredibly high. By comparison, the skill floor for BRD is very low, which is why a lot of people recommend it as a first DPS job because it is so easy to pick up and learn at that most basic level.
I do agree with your other points though; BRD massively out-supports MCH with Foe’s, Battle Voice, and its passive crit buff (and even with Nature’s Minne, which is a free Convalescence on the MT every 45 seconds), but I suppose the developer’s answer to this is an increase in personal DPS on the part of the MCH. They are higher in personal damage output compared to a BRD (by comparison, they also suffer more than a BRD by the lack of a DRG, since BRD at least has DoT damage and the ticks are not reliant on piercing resistance down but everything MCH does is). MCH is still meta, but it is usually the first to be subbed out for BLM, SMN, or, if the party wants to do triple-melee, MNK before the group subs out MNK (though BRD was subbed out during UCoB prog because Dismantle was very good, and BRD doesn’t offer anything similar to it to reduce the damage of certain attacks). Because groups that focus on optimization care more about rDPS as opposed to just pDPS, and rDPS will outweigh pDPS—BRD, NIN, and DRG all have relatively low pDPS, but ridiculously high rDPS because of their support.
Everything you say here is right save for one: unless it has changed recently, you do not hold Sidewinder for Raging Strikes. You actually try to line it up with the NIN’s Trick Attack, since they share the same cooldown timer. Refulgent is usually always used over Straighter Shot, unless SS is about to fall off and you need to refresh your DoTs. But you can actually clip them when they are >10 seconds remaining and not lose any potency by it (the IJ refresh is considered ‘FREE’), so I believe that most BRD opt to refresh them early so that they can Refulgent over Straighter Shot. You will always double IJ regardless of duration if Litany and/or Chain are up (definitely if both are up), and under certain other conditions, such as when there are 2 or more damage-increasing buffs up (Balance, Trick Attack, Brotherhood, Embolden-5, etc.).
Not necessarily. Even if a BRD is in the absolute worst comp for them (basically anything without a DRG), they still need to try and optimize for the buffs they have. It’s actually harder for a BRD to reach decent numbers when they are in a comp that specificially hurts them (i.e., no DRG). It says something about a BRD’s personal skill if, with a comp of NIN/SAM/RDM/BRD and with no AST (so SCH/WHM), they still manage to get high blues and purples in terms of percentile rankings.
Even with just a SCH giving me Chain, there have been times where I have been constantly double weaving Pitch Perfects or Bloodletters. Optimization doesn’t just suddenly decrease because you’re in a bad comp. Even in a bad comp you still try to optimize as much as you can with what you have. Again, as I said previously, the BRD guide has a section dedicated entirely to Iron Jaws optimization even in absence of Litany and Chain Strategem. Sadly, it’s even harder with unpredictable rBuffs like Embolden to optimize snapshotting, and RDM is only prog-meta.
I have to respectfully disagree that a BRD’s skill ceiling only increases if they’re in a meta comp, or a comp with a lot of rBuffs. Having nothing can still be a challenge in terms of pushing as much as you possibly can out of the job. I speak from experience (my current group comps have had no DRG, and very infrequently an AST, but I still managed to get 75th on Phantom Train with a comp of NIN/SAM/RDM/BRD a couple weeks ago...I also do not have BRD BiS as I only cleared God Kefka last week).