Everyone that is, except for then CEO and President Yamauchi. While the release of the system ultimately came at the very beginning of the late Satoru Iwata’s reign as CEO and President, the actual concept of changing the GameBoy into a two screen device was essentially pushed by only Yamauchi. Nobody on the GameBoy hardware development team liked the idea, nor did Iwata, who was tasked with bringing the idea to the hardware team.
As the story goes, that change ended up being a fundamental success, and it also officially marked the end of the GameBoy line of systems. We gained this new insight thanks to words from Satoru Okada, the now retired former head of R&D1 out of Nintendo of Japan.
“Actually, after the SP, we were working on the newest model in this range. The code name for this new Game Boy was IRIS, like the flower. The explanation for this name is simple: since it was for us the fifth generation of Game Boy, we chose the symbol of May (the fifth month of the year). In the Hanafuda playing cards, the month of May is symbolized by the iris. The project was moving forward at a good pace but during the development, something at unexpected happened. President Iwata then came to see me. He was obviously bothered and he said: ‘l talked to Yamauchi-san over the phone and he thinks your console should have two screens… A bit like the multi-screen Game & Watch, you see?’ Everybody is aware of this, but what people do not know is that at the time, everybody hated this idea, even Iwata himself. We thought it did not make any sense.”
This comes from an interview from Retro Gamer, translated by Japanese Nintendo.