^Trust me, his defenses do get amazing with Eviolite. His advantage over Shuckle is that it can burn targets with Will-O-Wisp and heal itself with Pain split. And it can attack with Night Shade. I have used him in a NU team and it did extremely well.
Here is a video: http://www.youtube.com/watch?v=71KR7DJseo4
EDIT: ^bad example