Makes sense.
As for another opinion - I really think Starswirl should've been the only ancient figure to come back. Like the Pillars are cool and all, but you can feel the writers not knowing what to do with all these new guys, especially after another six guys and gals gets introduced through the school.
I think the biggest evidence is Tirek vs. The Pillars - it is really sad how quickly these guys go down. Like the writing was like "hhhh, we need to get them out of the story now, let's just have Tirek win 6 on 1". If it were just a single character going against Tirek they would AT LEAST put up a decent fight, I feel like. They got nerfed worse than Princesses.
Which brings me to another point - I like the epilogue, but I'd rather have the finale as a three-parter. Have a huge battle rather than just a scene, and then you can end on the big rainbow laser after everything else fails to stop the Legion of Doom. The three parter format might also allow the Pillars to at least make an effort to protect Canterlot.
Also, on a pettier note, the fact that Mistmane's flowing hair is never explained bothers me immensely.