Chris Thorndyke is... not the worst possible child stand-in? Like, his existence makes sense. Kids shows do need to have at least one character that’s relatable enough to allow them access to the world of whatever it is. But he’s still ultimately kind of unnecessary since he 1) isn’t great at being relatable, 2) isn’t the only character in the show with the potential to act as a stand-in (and is certainly less interesting than the other options), 3) weakens the plot and setting of the show by acting as a weight and tether to the rest of the characters in a way that doesn’t complement the show’s premise, and 4) has way too much emphasis put on him for a character that doesn’t fit in with the other characters in the show and isn’t all that likable.
After the timeskip, these issues become way less notable, but only because by that point he mostly gets relegated to side character status and doesn’t have too much bearing on the plot and direction of the show. Also, he’s significantly more likable. In the first seasons, though, Chris’s spotlight ends up just overall weakening the show, and let’s take a second to walk through exactly why.
The number one thing that a child stand-in needs to be is relatable to the kids watching. The point of Chris is for the audience to see the bond Chris has with Sonic and his friends and feel like they’re in on that; Chris may not be a supersonic hero, but he hangs out with one, so that makes him (and the audience) cool by proxy. However, Chris himself doesn’t really do much to support that image. For one, he’s super rich and the only thing that seems to go wrong for him is that his parents aren’t around a lot, because they work. While those would be fine on their own, anyone watching would love being put in Chris’s shoes and the parent thing makes sense and adds something to his character, the fact that Chris nonetheless is very moody (against what the audience might feel in his situation) and in fact ends up causing a significant number of the show’s conflicts for no easily understandable reason makes him seem a lot less like someone the audience can relate to than someone the audience is supposed to have an opinion about, good or bad.
Compare to another audience stand-in in the Sonic franchise, the avatar from Sonic Forces. Whether or not you think the avatar was a good inclusion to the game, you probably don’t have too many strong opinions on them as a character; you aren’t supposed to. They have an impact on the plot, but not because their personality is a given way that makes them take given actions; their impact is supposed to stand in for your impact, and their relationship with Sonic is supposed to stand in for yours. Not all stand-ins need to be THAT much of a blank slate, of course, but giving a stand-in traits that could make them in any way unlikable, someone the audience could conceivably disagree with, is very counter-intuitive toward making them relatable and, thus, an effective stand-in.
Chris acts halfway between a stand-in character and his own unique character and, as a result, ends up mostly failing at being either.
2) He didn’t need to exist.
The reason why the production team probably thought Chris (or, more generally, a stand-in character) would be necessary for Sonic X is because Sonic is meant to act as a larger-than-life hero; that is, they didn’t want to sacrifice Sonic’s static moral-touting character from the games in order to make him a more relatable, growing protagonist that could carry the story. As such, they felt they needed to add a new character who was meant to grow and change along with Sonic’s lessons in heroism.
The problem is, not every character in Sonic X is Sonic, and the other characters could have played that role just as well, if not better.
The first name that comes to mind is Tails, but Amy, Cream, and even Knuckles have also been used in the past as foils to Sonic, making mistakes and changing in response to Sonic’s actions in the exact way that Chris was made to. In fact, this even comes up in the show; at multiple points during the Sonic Adventure and Adventure 2 arcs, Chris ends up doing the same things Tails or Amy did in the original game, but with significantly less impact since he... well. He isn’t Tails or Amy.
This all adds up to both Chris’s inclusion feeling redundant and the non-Sonic main characters feeling underutilized. In particular, Chris’s arc feels like it would have made a lot more sense and felt more meaningful if it was given to Tails, who has in the past had arcs based around feeling like he needs Sonic in order to be important or successful. In fact, if Chris’s spot was given to Tails, that arc would make even more sense since it would be able to actually be resolved; Chris’s arc never ends up resolving, since... he does end up needing Sonic, actually. Without Sonic, he isn’t really all that interesting. That particular arc would work much better on Tails, who is a VERY interesting and fun character, even without Sonic.
This point was already touched on earlier, but Chris’s inclusion isn’t just unnecessary. It actually, in a way, takes away from what the show could have been. What he ends up becoming over the course of the first part of the show is a stable rock that Sonic and the rest of his friends can orbit around but always come back to; he becomes the arbiter of the show’s status quo, if you will. This is a problem because the status quo he sets up isn’t one that works well with this particular set of characters.
Sonic’s whole shtick is that he’s a free spirit who doesn’t like being tethered to anywhere, anyone, or anything that he doesn’t want to. You’d think that one of those things he wouldn’t want to be tethered to is a mansion where he has to hide against his will, or a kid who clearly can’t keep up with him. In fact, this comes up in the second episode; he tries to leave, but Chris ends up convincing him that Sonic needs his help, only for it to turn out that... really, he didn’t. He needed Tails’ help, but again, Chris isn’t Tails. Thus, by the end of the conflict, it’s been proven that Sonic really doesn’t need to stay.... and yet, he still does. He stays with Chris for his entire time on Earth, despite the fact that he really had no reason to outside of liking the kid, and he had plenty of reason to want to leave.
Okay, maybe if he just up and left, that’d make Sonic kind of a jerk. But the point still stands that Sonic isn’t really the sort of person that would go back to a mansion at the end of the day, hiding away out of “necessity” that he knows more than anyone isn’t necessary. The way the story frames it is as Chris helping, but again, Chris isn’t actually helping, and neither is his grandpa; everything that the status quo perpetuated by Chris’s continued existence in the story provides is either unnecessary or actively detrimental to the end of seeing Sonic do cool Sonic things! It ends up feeling very forced, and you can’t help but feel that Sonic and friends would be doing much better if left to their own devices, not needing to constantly deal with a friend that doesn’t and can’t help. Sonic doesn’t need to slow down for Tails or Amy or any of his other friends, but he does for Chris, and that isn’t fun to watch.
Chris just doesn’t have a place in the story, and forcing it makes him feel like a nuisance more than a likable character.
This is the big one. Sure, Chris isn’t a good character for the show he’s in, but that wouldn’t be such a big deal if he weren’t made so important so constantly by the narrative.
Nearly everything that happens in the show has something to do with Chris even when it doesn’t need to; he tags along on adventures he can’t possibly help with, he’s always given input on decisions that have very little to do with him, and he ends up causing way more conflicts than he resolves. The result of this is that, wherever he is and whatever he’s doing, he feels shoved in. The viewer simply can’t get a break from Chris Thorndyke, the stand-in, while characters that are meant to draw their attention, like Knuckles (in particular), get shunted to the side and used only sparingly.
While Chris has all the traits and makeup of a side character (and maybe even an alright side character at points), the way he’s presented is as not only a main character, but THE main character, maybe even more than Sonic! This is despite all of the problems mentioned earlier and the more general fact that he just doesn’t really fit in with the rest of the cast.
For all intents and purposes, Chris Thorndyke is Sonic X, and as a result, Sonic X sometimes feels forced and pointless.
Now, I personally really like Sonic X, actually! It has a lot of things that I absolutely adore, like the characterizations of most of the Sonic characters and the occasionally very interesting attempts at telling original stories that are still based on the setting and characters that the gameverse set up. But still, it has a lot of problems, and a lot of those problems were either directly or indirectly caused by the unnecessary inclusion of Chris’s character.
Chris as a character isn’t terrible; he’s just a kid. The Sonic series has a lot of kids, some of which do much less than Chris does. Nonetheless, the way he was integrated into the show was just so messy, pointless, and ultimately harmful to the story as a whole that I can’t help but think the show could have been much better without him.
(He was perfectly fine in the Metarex saga, though! Again, they managed to fix most of this for the last season. That’s good, at least.)