I agree, mythic plus has mainly turned into PvP where your primary goal is to interrupt as many casts as possible and CC the mobs as much as possible.
At the same time, PvP has becoming more like mythic plus with CC durations being nerfed and PvP tier sets having the same bonus as PVE tier sets.
There is absolutely a way to make mythic plus more challenging without so many interrupts.
When the primary difficulty of mythic plus becomes the interrupts, then the meta shifts to classes that have lots of interrupts - VDH, prot paladin, boomkin, resto shaman.