You are coming at this from the IRC point of view.
The problem is that Twitch Chat is not IRC.
It’s Twitch’s own brand of chat that borrowed a fair chunk of the IRC spec, and just happens to have a IRC end point that works enough for a IRC client to connect to it.
Most of what TMI does is outlined in this document https://github.com/justintv/Twitch-API/blob/master/IRC.md
It sounds like you have taken a off the shelf IRC bot and tried to apply it to Twitch, which frankly is just wrong.
Since rather than relying on how ever the hell you are authenticating users to your bot, you should only be checking the full username, no need to deal with the hostmask, and then you wouldn’t have xdrtankheadx having access to root on your bot… Which doesn’t even sound right at all…
You can whisper bots so your second point is moot, it’s available right now. I myself whisper control commands to my own bots. And this would be the “DM” method to use in this case.
I don’t think we need or want the IRC access levels and it’s not the approach Twitch is going to make to it’s chat. But I think your suggestion of this is considering Chat as IRC, which is isn’t.