You differentiate between the types as platform and non-platform, but really they both come down the same thing: pay attention and do the mechanics correctly, or fail.

The difference really only comes into play much later, when everyone way out gears the fight, and may be able to just cheese through "non-platform primals" without bothering to do, or even know, the mechanics.

imo if someone is unable to do the mechanics properly, they do not serve to clear the primal when it is current. Maybe unpopular, but that is my personal opinion.

Having said that, by your definition, Ramuh Ex is not a platform primal, and in my experience of roulette, this is by far the hardest primal to pug. It requires a degree of co-ordination, people paying attention, and managing mechanics accordingly, and a large portion of the playerbase just seem incapabale of doing that. I reached a thousand mentor roulettes yesterday, and have only ever cleared Ramuh Ex once whenever it's put me in there.