If we are talking world first clears I would take these kinds of complaints more seriously, but most of these fights are just doing mechanics in a memorized pattern, only a few spots of rng which is usually quite controlled compared to actual rng. The rest is knowing how to play your job which quite frankly everyone should at least know this by minimum no matter what content they're on.

Then again most "casual" content in this game is the equivalent of mindless button mashing made easier by gear so we can just pull and spam aoes, so I suppose the lack of mid tier content is an issue since the gaps between what is considered mid tier (ex roulette) and raid tier is so wide.