Well, I thought the Superponies episode was good for Spike, in the sense of giving him a better sense of purpose. Except the the show undercuts it all by making him screw things up again and again in other episodes (It Ain't Easy Being Breezie is the worst offender), and then does the whole concept better in Equestria Games.
Anyway, with regards to Twilight, I do agree with what Lucas said about the whole point of the show being all the ponies coming together and Twilight learning from that (Magic of Friendship and all that jazz). And given that the bulk of every season is about just that, I think it's doing a good job going along with that thesis. But I also contend that all those lessons still revolve around Twilight being the primary figure, given both how she relates to whatever overarching plot is happening at the time and how absurdly overpowered she is as a magic user anyway. All those vital friendship lessons and interactions she'd had over the season come into play in the opener/finale. Without them, she wouldn't be there, and by extension that's the end of things. The show is still arguing that everything friendship-wise matters most, it's just showing condensed arguments as to why. Plus, all the magic she's pulling off still tends to relate to her friends being right there (especially in the S4 finale), so it's not like the others are totally absent or anything.
I should also say that I don't lean too heavily into the ideas I'm spouting above. My favorite part of every season is always the inbetween stuff rather than the "Big" episodes, and I'm a sucker for all the group dynamics anyway.