No, I don't think so.
Many think that The Last of Us 2 should star completely new protagonists, because "their story is complete", or "Joel and Ellie aren't franchise characters", or "The Last Of Us 2 should show us more of the world", or "continuing Joel and Ellie's story could ruin the first game", and "Naughty Dog will make a great game no matter what".
Is their story really complete
The Last Of Us did have the perfect ending, but that does not mean they can't continue Joel and Ellie's story.
Godzilla, Jurassic World, and South Park: The Stick of Truth, all had perfect endings as well, that don't need sequels, but they are all getting sequels anyway.
And if South Park can continue the story of a voiceless character named Douche Bag (that is seriously the main character in Stick of Truth, I am not even kidding) I'm pretty sure The Last Of Us, can find a way to continue character as well written and acted as Ellie
Are Joel and Ellie franchise characters.
Many say that Joel and Ellie aren't franchise characters, because of how well written they are, and how much you can relate to them.
But isn't that the kind of character that should have a franchise?!?! Seriously "I want them to make new protagonists because I liked the old ones so much" makes no sense at all! Changing the protagonists is what you do when you DON"T like the old ones, not when you DO!
I can understand not wanting to milk out the same characters, but The Last Of Us has only one, kind of short game. I can understand not wanting more of Joel and Ellie, if The Last Of Us was already a trilogy(like God of War, or Uncharted), or if it was a 30+ hour game, but it's just one, rather short, game. Compared to other characters, like Kratos, Nathan Drake, or Mario, we really don't get a lot of Joel, or especially Ellie.
My favorite part of The Last Of Us, was the points were we got to play as Ellie, but I felt we didn't get enough of those, like Naughty Dog was teasing what a full game with her would be like. Even the prequel DLC felt to short.
Ellie is a really fun character to play as, and I would love to see more of her.
I think more franchises should be centered around characters like Joel or Ellie. I want characters who I want to see come back, not characters who I don't care about, that are just card board cut outs of characters (like Kratos in God of War).
Sure The Last Of Us isn't called "the adventures of Joel and Ellie", but Uncharted ins't called "the adventures of Nathan Drake" but anyone who's played Uncharted knows it's about Nathan Drake. Each Uncharted doesn't tell the tale of a different treasure hunter, they are all about Nathan Drake.
The Last Of Us 2, without Joel and Ellie would basically be, a Dead Rising game.
Dead rising, is a game that does change it's main characters in each installment, and they are usually quite successful.
However the difference between Dead Rising and The Last Of Us, is that, NO ONE CARES ABOUT THE MAIN CHARACTERS IN DEAD RISING!!!!! The main appeal of Dead Rising, is the gameplay. Dead Rising does focus on it's world way more than the characters. But even Dead Rising 2 brought back the protagonist from the first game, in a DLC, and made him kill the new protagonist.
The Last Of Us, however, became so popular because of it's story, and characters a good number of people don't even like the gameplay of The Last Of Us, though I do, but those who don't like the gameplay still like the story and characters enough to like the game.
If The Last Of Us 2 had new Protagonists, it would tell us that Joel and Ellie's stoy didn't matter, and the only thing that does matter is killing zombies and, the post apocalyptic world that, let's be honest hear, the WORLD of The Last Of Us, is nothing special.
It's Just a post apocalyptic world, they're a dime a dozen, seriously, Fall out, Horizon (New game that was announced at E3 2015), Enslaved, The Hunger Games, Oblivion, Left for Dead, Dead Rising, even an episode of Family Guy had a post apocalyptic world.
The thing that makes The Last Of Us so special, and one of the best games ever, is Joel and Ellie (especially Ellie, she's awesome!). Without Joel and Ellie, well, I think that episode of Family Guy were the world ends has a more interesting world than The Last Of Us does.
Before you think I am hating on The Last Of Us, I am only "hating" on one small detail of The Last Of Us, that it's not really about any way. I love everything else about the game, it's story, the combat, the online, all amazing, and I don't hate the world of the last of us, I just don't think that the sequel should focus on something that a lot of other games have. What no other does have, is characters like Joel and Ellie, and that's what makes The Last Of Us so awesome, and is what the sequel should focus on.
Does Ellie find out about Joel's lie? Is she cool with what he has done? How did Joel become the brutal survivor he is today? these questions are what the next game should be based on.
The same story, but with different characters, would be a pointless story. It would just be repeating the first game. But with Joel and Ellie, you have the opportunity to move the story along, as a good sequel should do.
Naughty Dog can avoid "ruining" it's ambiguous ending, and still have it feature Joel and/ or Ellie, by having multiple endings, so it would still be up to the players interpretation, and it would have more replay value.
Can Naughty Dog make a bad game?
Yes, anyone can make a bad game, even Naughty Dog. Before Uncharted, Naughty Dog was really nothing special, they just made cartoony kids games, like an off brand of Nintendo.
It wasn't until Uncharted, that Naughty Dog was able to show it's ability to make these amazing games.
If Naughty Dog ever makes a flop of a game, and let's face it, it's bound to happen, their's a good chance that flop could be The Last Of Us 2.
If The Last Of Us 2 doesn't star Joel and Ellie, personally, I won't buy it, I may rent it for the online, but that's it, The Last Of Us needs Joel an Ellie, period.