@bobVerge @Variousletters I agree, this artistic change for the manga adaptation is really disappointing.
Heck, it even doesn't make sense based on how Rimuru's Gluttony ability works. He can only consciously use Mimicry. Making a Chimera-like body isn't something possible without the soul willing it. But the body no longer had a soul prior to it transforming here. That doesn't make sense.
It was supposed to become a real ooze, the like of the absolutely terrifying ones seen in D&D(for example). An gooey mass that keeps on shifting shape, devouring and dissolving everything on it path, growing ever stronger the more mass it accumulates. THAT is worthy of being disintegrated to keep it from becoming a bigger threat.
A mere chimera-like body while it's in a Holy Field? That's not even a threat compared to the Ooze.
And even more importantly, the Ooze devouring Hinata's soul attack rainbow sword was done off panel! It absorbed and dissolved a super high tier weapon like it's nothing. (also meaning that Great Sage has now analyzed the properties of that sword)