In the Krys/Lyra situation, Lyra basically replaced Krys and the two never really coexisted in any games. But for the BW and BW2 protagonists, they were distinctively different as evidenced by them coexisting (though not physically) in BW2.
Not to mention that the idea of Crys and Kotone being separate is questionable, and can be incorrect. What do we know about this other than the designer making Kotone from scratch?
However, as time goes on, it seems like an attire change is the easier way out. The BW2 arc has not progressed beyond the prologue, and XY are on the horizon (if BW's release was any hint, the writers would feel pressured to start the XY arc alongside with the games' release). I don't really think the writers have the luxury to build two (or three if counting Hugh) new characters from scratch. Platinum and HGSS were cut short in the magazine version and completed in volumes, but there were essentially no new protagonists to introduce, so the writers only had to cater to the plot. If they decide to create a Black2 or White2, I doubt there will be much time for characterization. With each new protagonist, I guess it's fair to say you need at least 10 chapters or so just to build the character before something solid happens with the plot. There is already doubt on how much they can develop Hugh if he plays a major role in BW2. If you add two more, I can't imagine a fulfilling arc. I'd really hate to see two completely forgettable protagonists joining the Pokedex Holder group.
But we have
Pokémon the Comic coming soon, this means we will have three magazines serializing the manga. There's no reason they can't use one of them to serialize BW2, and even with the whole magazine launch process thing, I don't think it'll take more than until Octoboer to release it.
Um, yes there is. For one thing, has there ever been a scene in the games where Hilbert/Hilda and Nate/Rosa were together? No there wasn't. As far as Nate/Rosa are concerned, Hilbert/Hilda are only legends. Even Cheren, Hilbert/Hilda's best friend, thought that it would be easier to find N over Hilbert/Hilda in the games (and N was supposedly in another region). Hilbert/Hilda may as well not exist. In the manga, it would be better for Hilbert/Hilda and Nate/Rosa to coexist as one character than to banish the first set into nonexistence.
We also never had any scene where the
Crystal male and female protagonists interacted. We still got both in the manga. The same happened with Silver in FRLG. There's really no reason for Kusaka to banish Black and White if he used Kyōhei and Mei. We saw BW2-only characters in the BW League, there's really no reason for Black to be missing by the start of BW2 and return with N for the final battle.
Also, this "Tōya/Tōko may not exist" is idiocy, We were explicitly shown they exist by
playing as them, having them mentioned by Trainers in the routes,
playing as them, having them being mentioned by N, and
playing as them. Did I already mention we played as them. If you say they may not exist, you're claiming B/W never happened, which leaves with a
plot black hole, or even that N and G-Cis in the first game were defeated by a collective hallucination.
And plus, Nate/Rosa has to be main characters. But they already ran out of games to name them after after Hugh. (And no don't suggest Black2/White. Not only is it completely ridiculous and unhumanoid but when was the last time that a character was named after any form of remake/third version?)
Platinum...
And before her we got Blue, Yellow, Crystal, and Emerald. Kusaka always uses the names of all the main games, FR/LG and HG/SS weren't used because they are remakes, which are basically "this is what the game would be like if we made it nowadays", so maybe Kusaka counts them as the same thing as the original ones. But B2W2 aren't remakes, they are sequels, which, for this Generation, means "the third version". I'm pretty sure he'll work out "Black 2" and "White 2" in some way or another even if it's just for a nickname, and if he doesn't, he'll just use the in-game names, like he's doing with Hue.
There are also other ways of working "Black 2" and "White 2" as names for them. Someone on the With The Will forums suggested translating them to Japanese as "Kuroni" and "Shironi". Another possibility I thought is giving them full names, with their surnames having the words "black" and "white", and names containing the number "two". There are many Japanese names containig numbers on them, such as Sei
ichi,
Mitsu (which is literally just the number "three"), and
Gorō, so Kusaka could easily have the boy being named "
Jirō
Kurosaki" and the girl "
Futaba
Shirakawa", or any other name using these kanji. This would, however, be hard to adapt in English and other languages since, at least as far as I know, there aren't names containing numbers in Western languages, but I don't care, and probably nor does Kusaka since he's not writing it for Western audiences.
More to the point, "running out of names" is not a valid reason to say Kusaka won't use those characters, as he can always play with these in never-before seen ways, such as the full name suggestion.