Junichi Masuda has been a key member of the Pokémon development team since the very beginning. In the early days, he served as a composer, programmer, and advisor before eventually becoming an Assistant Director on Gold and Silver. Ever since then, Masuda has jumped back and forth between wearing the Director and Producer hats, and he's currently serving as Director on Pokémon: Let's Go, Pikachu and Pokémon: Let's Go, Eevee.
While Masuda sees Let's Go as an important evolution that could pave the way for another 20 years of Pokémon, he may not be the one to provide hands-on direction going forward. Masuda recently sat down for an interview on the official website for The Pokémon Company and answered questions regarding the development of Let's Go. Near the end of the interview, he indicated that the upcoming Switch games would likely be his last as Director.
Masuda: I was the one who worked on the base game concept document for Pokémon GO, and even in that original concept, I had the idea of introducing new Pokémon through the mobile game. I wanted to realize that goal by creating games that could connect with Pokémon GO and feel somewhat similar to it without feeling like we were copying it. Given my involvement in Pokémon GO's development, I felt that I was probably the best person to direct these games.
It was also interesting to work with Nintendo Switch. There's a lot of technology packed into the hardware that we were all trying to discover at GAME FREAK. For example, developing the Poké Ball Plus and working with Bluetooth to facilitate the connection with Pokémon GO were both very interesting things that I had a chance to work on as the director this time.
But at the same time, it's important to have the younger generation at GAME FREAK take over the development of Pokémon as a series. I do believe this will probably be, in terms of the main Pokémon RPGs, the last time that I work as the director.
While Masuda may be stepping away from the Director role, he'll almost certainly continue to be involved with the franchise. As the interviewer pointed out, Masuda did not serve as Director on Omega Ruby, Alpha Sapphire, or any of the Sun and Moon games. Instead, he chose to take more of a supervisory role as Producer.
The third generation remakes and Sun and Moon were directed by Shigeru Ohmori, while Ultra Sun and Ultra Moon were directed by Kazumasa Iwao. Perhaps one or both of these talents could step up to become the primary Director for the series going forward. In any case, it's hard to see Masuda abandoning the franchise altogether after 20 years of service.
Source: The Pokémon Company