Mario always gets the spotlight. This undeniable fact makes one wonder how the rest of the Mushroom Kingdom and their affiliates feel about forever playing second fiddle. Almost every series or game that he's involved in has to have his name front and center. Super Mario Bros., Mario Vs. Donkey Kong, Mario Kart, Mario Strikers, Mario and Sonic at the Olympic Games; the list goes on through the universe, far past the reaches of Rainbow Road in outer space. Even the original Luigi's Mansion was a quest for Luigi to find Mario. The original Donkey Kong has players controlling Mario and resorting our King Kong-esque hero to playing the villain. It makes sense then that many of Mario's friends have fallen by the wayside. Yoshi is the ideal sidekick. He's always there for Mario, even if their relationship means endlessly spawning new eggs to keep up with the rising death toll his mustached master inflicts upon his species.
Mario smacks Yoshi on the head to make him attack, rides him, and drops him off of cliffs; he's downright savage to his dinosaur pets. Yoshi doesn't make that grunting sound when he briefly runs in mid-air because it's cute, he's literally struggling to survive. That's the sound of Nintendo's true Sisyphean struggle; the helpful dinosaur lives in a Groundhog Day loop where an Italian plumber finds endless scenarios to beat him at sports or cause him physical harm.
That's not to say that Nintendo has never given him any sign of respect, however sparse it may be. Despite Nintendo starting to drip-feed games like Captain Toad and Yoshi's Wooly World out to the masses in more recent years, it's just not enough. Justice must be served. The Mushroom Kingdom and Nintendo both owe Yoshi an insurmountable debt of gratitude, and it's time to make good on their restitution. Luckily, there's a way that they can right the wrongs of the past and put Yoshi on equal footing with the rest of their characters. Once the Mario movie comes out, Yoshi should receive the next movie.
While this may seem like an odd idea to some, there's actually a whole lot to go on in order to start writing a Yoshi movie. Where do the Yoshi come from? Why do they come in multiple color variants? These are just the first two obvious questions, but using the locations and items around the Mushroom Kingdom there are even more possibilities. Bowser, for example, has many minions.
What if it turned out that Bowser had a hand in bringing the Yoshi to the Mushroom Kingdom with the intent of breeding and raising them for evil? It would be an interesting twist to see their kind brought in with the sole purpose of destroying Mario, only for the inherent good within their kind serving to put the kibosh on such a scheme. Taking a comedic angle, the film could explore Bowser's fury slowly mounting as each training exercise only serves to make Yoshi cuter, more friendly, and heroic. There are other possibilities as well that could expand upon the Mario lore while also serving to make a slightly more complex Yoshi story.
Looking at Rainbow Road again, there's the possibility that Yoshi is an alien. He's green after all, who's to say he didn't come from a planet of adorable little dinosaurs? One day, a baby Yoshi accidentally exits his planet which is just past Rainbow Road. As he tries to make it back, he falls through Rainbow Road and the prism splits him into several different colored versions of himself. At the same time, a race is going on between Mario and friends on that very course. Upon winning the cup, Mario and friends see the Yoshi and, not knowing where they are from decide to take them home with him as a gift to Princess Peach.
However, Bowser and Donkey Kong have hatched a plan for revenge after losing to Mario for the last time. They kidnap the Princess and lie in wait for Mario's return to the castle. With the help of Wario and Waluigi, they capture Mario and Luigi as well. The Toads around the castle have already been restrained, meaning that there's seemingly no one left to come in and save the day. But they forgot about one prehistoric pal, the enthusiastic and agile Yoshi.
The Yoshi are still in a gift wrap box which Bowser's kids can't resist opening upon ransacking Princess Peach's castle. Out fly the Yoshi, who now can tell that their new friends have been taken away. After defeating Wario and Waluigi they band together, all colors of the rainbow united in a way that Skittles can only dream of, embarking on a journey to Bowser's lair. This route may prove to have more legs than a simple Yoshi comedy, as it would have more of the Mario stable of characters as well as higher stakes. It also would prove quite entertaining if given to the correct studio to work with. Hopefully, these ideas can come to fruition, instead of getting thrown off of a cliff like so many Yoshi before it.