The rumor is false, but I certainly wouldn't be opposed if it were true. I don't like the theme at all. The sets of the first wave were okay, but the 2017 sets are abysmal.
And it seems Brickset needs to check what they report: they also had an article on the rumor of Lego Dimensions ending, which was also false.
Regardless, I want a true Castle theme and a true Space theme, not a failed merger of both.