Well, I don't think a capture episode can be considered as a filler, regardless who's catching it.
Profesor Oak doesn't need another pokemon. He has to take care of Ash's hoarding problem.
The Pokemon Centers in Japan are having a huge Rotom promotion near the end of April, not quite sure what the air date of this episode is lined up to be, but something is definitely going on with Rotom for it to get all of this promotion.
You aren't suggesting an evolution or a new forme are you? I guess it could be and we could get it in the next CororCoro, or the one after and then it could be in this episode, but I assume it would've at least hinted to that in the title or a summary of the episode. Unless it's advertising for an upcoming Rotom giveaway.
I just hope that it won't be similar to that other Rotom episode.
focusing on Rotom and all of its forms, just like the episode scan showcases. (To be fair, they have done other promotions of Pokemon that didn't line up with anime episodes, but this one seems close enough together to draw that conclusion.)
Heh, I actually posted earlier in the thread thinking it might be a new form
I don't think we'd see a new form/evolution in this episode per se, but it seems to be going somewhere that it's implied that Oak wants to study them, in that there may be a reason later for this?
Or it could just be an episode to show off Professor Oak and Rotom, whether it be for another promotional purpose like a future giveaway or because they want to have another Rotom episode.
I can't wait to see Iris and Cilan interacting with Professor Oak in person and maybe Ash could tell Iris and Cilan more about his older Pokemon and previous journeys, unless that will happen when Ash goes back to Kanto.