I'm going to have to agree. Mew, for most intents and purposes, is better than Togetic@Eviolite. I suppose you could argue that Togetic has Wish, Yawn, neutrality to Dark, resistance to Bug, immunity to Ghost, and immunity to Ground to separate itself, but I'd still always rather use Mew to Baton Pass.
As for Rhydon@Eviolite, while it does make him bulkier than Rhyperior, I don't see him being the better choice. The reason? He still has a horrifying set of weaknesses. Ground/Rock is meant to be abused as an offensive typing, and Rhyperior has higher Attack and the ability to hold items like Life Orb and Choice Band. He even has Solid Rock to slightly make up for the defensive difference, so I'd rather use him.