Twilight Sparkle: <sigh>
DM: You alright?
Twilight Sparkle: Oh, sorry. I'm just a little wistful, I guess? I mean, here we are talking about where our characters are going to end up in the epilogue, and... Well, it's my first campaign, and I'm really attached. I'm not really ready to think about it ending just yet.
DM: I getcha. And don't worry. We're a long, looong way from any finale for this campaign. That is, if you all are up for continuing, even after this Discord arc has run its course.
Applejack: Yeah, no problem. Still a hoot.
Pinkie Pie: Who am I gonna organize parties for if we stop?
Rainbow Dash: Someone's gotta look out for you Diplomancers!
Fluttershy: ^I really like hanging out with all of you...^
Rarity: Everything has to end eventually, but there is still much joy and adventure to be had.
Twilight Sparkle: Thanks, everyone.
DM: <sniffle>
There's a fair amount of filler episodes that aren't likely to show up except as a source of screen caps. For instance, we're well past the point where Flim and Flam would make any sense as opponents. And the Cutie Mark Crusaders are their own campaign for that matter.
So what do we have left for adventures? Sombra has been teased a few times, so then we'll still have Tirek, Starlight, and the finale? Any episodes in between that would work?
Well, there's the Daring Do villains, beasts like the Chimera and Timberwolves, everything from the movie...heck, if the party was willing to try out GURPS Supers for a lark, we'd even have a fight against The Mane-iac. I think it's safe to say that we don't need to worry about running out of content, though making it compatible with the tabletop campaign framing device is another matter entirely.
If we're to get a Power Ponies arc, I think it would work better with Champions. PlayerTwilight is just begging to be the kind of player who gets a series of "no, no, no, definitely no, that power has a stop sign for a _reason_," GM comments.
There is I Grogar, the great talking goat that is not Discord in a disguise as a villain, I absolutely assure you that I'm not Discord disguised or him invisible with a hand in my back opening my mouth as he talks
It is rare in my experience that a campaign lasts long enough to complete those long-term goals. I've run about... Three to their completion? No, four. And that represents maybe 40% of all the campaigns I've run. Only one game as a player I can remember completing the story, and it wasn't a long campaign. So many of them never got to a conclusion. Most of the time real life is what gets in the way.