Would be amazing, but I think Iga probably enjoys not working within the constraints of Konami.
If he ever did it, I would think he'd do it as a contracted project for his company ArtPlay, rather than actually becoming an employee again of Konami. So, conditions would be different, sort of. There'd be an approved budget and timeline, there'd be milestones to hit, there'd be a producer with oversight, but there'd also be some flexibility in being an independent contractor rather than inside the company, and a different weight of responsibility. Circumstances just wouldn't be the same, for better or worse. (Also, whatever bosses and company direction Iga felt compelled him to leave are long gone now... not that things got
better at Konami since then, but if they actually brought Iga to the table, a future Konami would not be the same as 2014 Konami.)
...Don't see why he'd ever do it, though.
Bloodstained gives him ownership, and it has been successful, so he may not need to explore further options. He can make another Bloodstained, he could make more of the Curse of the Moon games, he could start something new again... the man's got options that the first Bloodstained and the 8-bit-style games bought him. He doesn't need to go back home, and not many even fans are looking at the Castlevania line thinking, "Oh man, something's missing in this canon..."
(Also, let's not forget that Bloodstained had its own prolonged period of development and launched to some acclaim but not universal applaud, and the sequel is nowhere in sight 2 years later, so it's not like he's the goldenboy that Konami would throw any and all money at either. Such a partnership could be a great relationship and result in a highly-sought-after Castlevania game, but it could also result in more frustration on all sides.)
