As usual, I don't see the need for updating sprites, unless they are really wonky or broken. Especially the he Lacula looked great before the update, and I don't like the new version. At all.
Like Sakuhanas, they are comparatively recent dragons, so I don't understand why an update should have been necessary so soon after their release.
I do understand the wish for updating Thunders and Magis, though, and I think the new versions look good (didn't mind the old ones, though). The new Snows look pretty as well.
What I like about DC is that there are so many different styles of dragons. I do not like all of them, but I appreciate the different artistic approaches and efforts. Trying to streamline the sprites is no improvement IMO. But we've had this discussion before, so I won't elaborate.