After a week away, Sequel Square may be moving permanently to that bi-weekly model, but there will still be plenty of sequels to come. For instance, the OG brick of handheld devices is in line for a sequel, and it could be another blockbuster for Nintendo.
What the Original Offered:
Just about any innovation in the handheld gaming market sprang from this grey (or black) behemoth Game Boy. Over the years and iterations, there was still a simplicity to the design that ultimately boiled down to a few buttons and a directional pad. Game Boy Color, SP and so forth all gave gamers something new up through the 3DS/2DS, which even had a Nintendo first in a stable online structure for a handheld. Ask Nintendo: it was the software that made the system to the same extent as the features. Pokemon, Mario and the entire list of Nintendo properties have been on their handheld at some point, and that portable ability to take on a quick level is invaluable for Nintendo fans.
What the Sequel Would Offer:
The two staples of every Nintendo system - software and a new feature - should come to Game Boy Super (you're welcome, Nintendo Creative). The design, first of all, should seem groundbreaking and eye-catching; Nintendo has verbally confirmed their commitment for the hardcore of their fan base, so make something that makes the Vita look like a VHS tape.
The feature that hooks everyone, on top of touch screen, back light, color etc., should be the revolution of their online service that connects every Nintendo property into a single, digital hub. Call it whatever cutesy name you think of first (Nintendo World, Cloud Nin(e), Mario's Beach House) but put every property into this free-roaming, all-inclusive structure. Think of this as a massively-multiplayer hub where coins are the currency and mini-games break out randomly from races or jumping contests or whatever for more coins to buy clothes and customization options. This puts the casual up front for whoever just wants to pop in and customize their Mario look-a-like, but keeps it simple enough to allow hardcore gamers their instant access to actual games.
Those games should just be the Nintendo norm of quality, cleanliness etc. with a slight integration with this Nintendo World concept in a "Oh, now Marth has a section of the world because the new Fire Emblem is out" kind of slight. This Nintendo World idea would suck in eye balls at any kiosk and could make the insanely high price tag of this potential machine completely worth it. While this might sabotage titles like Animal Crossing and Tomadochi Life, having an instant over world and meta game out of the box for millions of customers would probably make up the difference.
Out of all of the Squares thus far, this one may be closest to the mark. The time should be coming soon for another handheld iteration from the Big N as 3DS sales are beginning to slow. But, alas, the future shall tell all in time. Check back in a couple weeks for another possible Sequel.