This has been discussed before.. It would be difficult to manage for one, you would need to have players create a login, and verify it in-game. And then have bans/mutes/kicks carry over.. Also, you won't know who is watching you as they wont appear in who's online, so we would need to add some kind of login.. Also you would just get someone constantly on the page, recording everything said.
As for upgrading Dave (not D.A.V.E), that would be complex to do, the things that can be done with him are limited, he needs to run fast, otherwise he will slow down the server.. Also, IP banning someone from the chat page would be pointless, you can renew your IP address.