Seriously though, the villains betraying Grogar wasn't "subverting expectations", it was literally right in front of our faces.

None of them liked working for "Grogar", he barely appeared or did anything throughout the whole season to warrant being "the Thanos of MLP", the trio spent the season working together to become a powerful threat and sowing the seeds of their betrayal, and you were honestly surprised "Grogar" got overthrown? Even if he was the real Grogar, this betrayal still would've happened.