Non-Vanilla pkayer here. I assume in addition to the content patches, Blizz did some class balancing. As the Devs release updated content, does this include those changes or is it only raid/dungeon content that is being updated?
Class balance is as it was in 1.12.1 (the end of vanilla). So there are no changes whatsoever regarding that, it only affects content (quests, loot, dungeons).
Gear gets tweaked and items are sometimes added. But the mechanics and damage coefficients of class abilities as well as all talents are in their 1.12.1 state and will not change.