This post is no longer relevant as the Twitch channel is now defunct, but I still stand by this policy.
To me, a Twitch host is saying "I like this broadcaster, and given the fact that you've watched my shows for more than a minute, I think you'll like them too." This is the superficial definition, as simple and easy as hitting the "host" button. This is enough to see a host as a good thing.
There's more to it, going into non-specifics, that colour the act of hosting in a darker light. A host is highly political. Whether spoken or unspoken, it shows at least some alignment of values between the host and the hosted. Oftentimes it's fine, an extension of the network of viewers and viewership where everyone wins.
My issue is that I have yet to find a broadcaster with which my values truly align. I'm not speaking on a personal level; that would be making far too many assumptions. Broadcasting, no matter how forthwith and "honest", still layers a personality with a film that obscures the truth of who they are. We are caricatures, putting on whatever skin we need to wear in order to go through with a broadcast. Make no mistake: broadcasting successfully for any length of time requires one to craft a ceremonial suit of armor, that mystical "thick skin" that allows us to face the public and all its vagaries, and perform.
Then there is the unspoken sense of reciprocity. What exactly motivates a host?
At the end of the broadcast I'm happiest releasing my audience to do whatever they want with their time. The last thing I want to do is burden them with the expectation of joining an alien community or asking them to split their support over a new face.
If a broadcaster I've been watching does something interesting (all the rarer these days, as I spend almost no time consuming livestreams), I'll mention it during my show. I leave it up to the audience to decide if they want to pay that person a visit and become one of their supporters. After all, that's how I'd like to be treated.
Addendum: don't seek to make other broadcasters your audience. It's way more trouble than it's worth. Seek the holy grail, that golden fleece of content creation: a viewer who's just there to view.