Dusk Lycanroc had a better build-up because it wasn't completely pulled off their asses; Rockruff had shown an admiration for both forms of Lycanroc since its debut (the wild ones in its capture episode, Gladion's Midnight Lycanroc, and Olivia's Midday Lycanroc), so it makes sense for it to get a form that combines traits of both
But Ash-Greninja is something they pulled out of their asses to give Ash a Mega
