Gotta tell you, we knew about all of these in Vanilla.
The only difference is how many people know. I assure you, skilled elemental shamans all knew how EM worked. Every single one of us knew how to get the double crit (and I didn’t even play ele, and I still knew). Every single frost mage worth the name knew how to get shatter combos. Every caster who could out-DPS wanding knew how to clip the end of their spellcasts (most of us had an addon for it with /stopcasting macros).
None of this is new. It’s just that new information vectors and a higher percentage of hardcore players in the playerbase have made it more common than it was.