When the whole point is to reference something that came before, fidelity to that something is not an unreasonable expectation. This isn't a new thing "incorporating elements of" Megazarak "we wanted to redeco Cyberworld Scorponok with a Megazarak-inspired color scheme". It's pretty straightforwardly "a remake of Megazarak", and as a redeco of existing tooling, the specific thing this release brings to the table IS the deco, so it'll be judged on those merits. And, I feel, fairly.
Mistakes can and do happen, and have happened, in the design and production process. It's not just a matter of a fan going "this is a mistake because this isn't what I want", it's someone with eyes going "okay, this isn't how this looks". The wiki has plenty of examples of honest, even admitted, mistakes.
And really, what's so bad about calling it that? An error is an error and it happens. And honestly, in this decade, in this forum, it's not like anyone's calling for the design team's jobs over stuff that's rightfully dismissed as small beer.
But to be fair, maybe it wasn't a mistake, and they wanted it that way? That's certainly possible too.
We won't know until we get the always-deeply-appreciated behind the scenes talk about it whether this was "yyyeah it looked different on my monitor" or "the wiki reference picture looked like this" or "I felt the blue was too much so I put a drop of gray in".
Maybe it was indeed a deliberate choice. And you're right, the team is free to make that choice.
But the audience is free to agree and like it as well, or disagree and dislike it. Or, imagine this, a bit of both: I like that there's way more blue now, replacing the blah gunmetal, but I don't like the shade of blue. (There's the red, too, but the point is made. At least Hasbro seems to be making things in proper black plastic now, rather than veeeery dark blue or brown or whatever.)
At that point, it's not them misjudging the color, it's them deliberately choosing a different color than the one the thing they're referencing uses. And there's degrees to that, certainly -- it's not like they chose lemon yellow instead of a less saturated blue -- but those degrees create room for degrees of agreement or disagreement.