I finally beat Pokemon X and have checked out Kiloude City. It didn't impress me much (The Battle Tower/Subway/whatever places typically don't interest me.).

What else is there to do in post-E4 Pokemon X/Y? I remember there's a blocked cave in the Terminus mineshaft and I'm guessing the Lost Hotel and Chamber of Emptiness have stuff I haven't seen yet... Is there anything else to find/discover?