I've just seen Se4 E21 "Testing Testing 1, 2, 3"
Finally, a good episode. It reminds me a bit of the earlier seasons; all the mane 6 in the same episode, unique expressions, some unique styles, genuinely funny parts & consistent character development.
What I find interesting is that Rainbow Dash is leading up to what Lauren Faust said she wanted at the end of the series, for RD to join the Wonderbolts. This is episode 21 of 26. Maybe each episode will have a character changing event which will leave Season 5 with some fresh content to write with.
By the way; if you focus on 04:06 of this episode, Twilight speaks without her mouth moving.
Expect animated .gifs of Rainbow Dash rocking on a chair.