The ending is probably going to be a high school graduation ceremony

[cider float 2,538]

I feel like the whole Equestria Girls will stay in high school and end when they graduate high school and go off to be adults. 

 

I can't think of what the fifth movie would be about though. Sunset Shimmer is finally over her guilt and has gotten the confidence to help others, Twilight Sparkle 2 has also gotten the confidence and understands responsibility now. So what friendship/emotional problems are there left to solve? Flash Sentry's absence of pony Twilight could stay a minor issue. 

[K1539 47]

Wellp there was that whole foreshadowing magic invasion thing. Maybe they have to unite the town against a lot of evil magic despots (there is no shortage for a place that wasn't supposed to have magic) Hell maybe the Drizzlings will get their powers back and try to open up a dimensional gateway to Equestria (another dimensional rift, this is a common theme it seems)

And maybe there's a Chrysalis or Sombre in the EG dimension who are just dying to sink their hooves into a juicy magic granting rock

[cmarston1 5,959]

If/when the concept of graduation gets explored in the franchise, I really hope we get that Sunset is homesick sub plot.

[Ganondorf8 11,365]

Since the three specials will be following the events of Legend of Everfree, I'm expecting Sunset and the others dealing with the magic leaking out of the portal. Who knows what other locations hae now been affected by magic and who may be corrupted as a result.

[Steve Piranha 29,432]

Before that, I hope Sunny meets the human counterpart of her family though