The dex is in beta, so it would be nice to find out where the kinks are before we start adding new things. Keep in mind what you would like to see and suggest them once the dex is out of beta!Here's a thread for bug reports: http://www.smogon.com/forums/threads/new-dex-up-post-bugs-here.3510811/
Suggestions for the dex should probably be held off on for now while everything is still constantly being worked on. Most of the suggestions people bring up are probably already known and being worked on. Once the dex gets out of beta, this would be the ideal place to post suggestions for it.