I don't have any skin in the game on the caster vs. martial arguments that are endless as I just play whatever build works.
My only observation is that the R7-R10 nerf was extremely crude and results in all casters doing less than 68% of the damage on R10 that they did before the nerf. I am not sure how any reasonable person can argue that wizard, warlock, caster fvs, caster cleric needed a nerf as they were already below-median builds before the nerf. This is on top of the epic strike nerf which hits those same builds hard as they were a major part of the rotation.
From a raid perspective I would always prefer to have exactly 1 caster with good cc in the group and no more, although 2 in too hot too handle is good but really you just want sorcs there or maybe 1 sorc and 1 ice druid. Melee have much better sustatined damage over time and dps is over-weighted in raids compared to quests.
From a solo perspective, casters are very good and have always had a niche as being the best soloer's. At the moment comparing my best soloing caster to my best soloing melee I would prefer my melee for 75% of the content and my caster for 25%, but some of those quests where a caster is better are extremely painful for a melee as you push skulls, e.g., Tavern Brawl which can be cheesed on a caster, Slavers II and of course nobody wants to do melee damage to the boss in Tempest Spine on R10 unless they are cheesing in a safe spot.
Much of the reason I prefer to solo on my melee for so many quests is the survivability and aoe improvements over time have been significant difference makers. My melee has better hp, AC, PRR and can stand in deliver in places my caster has to kite. Caster AOE Is still better, but my melee aoe is more than good enough. In most quests my melee clears the dungeon faster, but by a small margin. In some quests a caster is just way better at soloing it, although there might be some tricks and tips I am missing that would make my melee experience better on those quests.
Going forward I will have one solid caster for soloing and my other solid characters will be martial. In most casual raids caster contribution is pass/fail vs. scaling meaning that if you spec a first life caster for LH raiding they will perform the job effectively and you won't notice much difference between a complete character and a first-lifer. So I'll make a few first-life casters for raiding when the role is needed - which it is needed more frequently lately as fewer people are bringing casters to even casual raids.