There's been a lot of people saying "Character Y won't be in the game because they're just a clone of Z." There was also a lot of chatter like this when people were speculating the roster for SC5 years ago. So I decided to make a quick video to compare some movesets to see how similar characters are. I think someone else did something similar for Hwang in SC1 some months ago.
Quick disclaimer, I only compare around 10 moves per character (I made a quick list of basic inputs which I go through). This took way more editing time than I expected and comparing more moves would have taken ages. A better comparison would be to compare high level gameplay as that will showcase the popular moves and the general playstyle, but I think this is still pretty interesting.
The comparison video (you can use the youtube video player to reduce playback speed):
I was surprised to see characters like Mitsurugi and Yoshimitsu (generally seen as super unique characters) share some basic moves. Based on this comparison, it's easy to conclude that Rock has the least to offer. Not only are a lot of his moves the same as Astaroth, he lacks the variations of those moves Astaroth can do. I'd be curious to hear from someone who's played Rock on how different he is from Astaroth.
This is also an interesting look at how Namco designed some of these characters. When making moves for a character with a similar style as someone else it looks like they tried to make new moves with a similar flow to the original character. For instance, Sophitia's and Cassandra's 44B move. Sophitia spins her sword in a circle around her while Cassandra spins her shield around. The two moves are completely different from a technical point of view but they look very reminiscent of eachother. And then there are a few moves which look very different but seem super similar from a technical standpoint (like MItsurugi's and Yoshimitu's 3B).
I'm sure Namco must have had a lot of discussions about this when determining the roster, where they consider skipping characters with the same weapon even if the moveset is unique. I'll be disappointed if a lot of these characters are skipped because of that. I personally find Cassandra a whole lot more fun to play as than Sophitia.