I think the frequency of asking Twitch chat what to do has been overblown. For instance Rich generally only asks a deck designer about plays or sideboarding when it's a deck he is unfamiliar with. Watching people stream new decks is interesting and hearing what the designers have to say is educational. If a streamer is playing a deck in an important tournament that he knows well, he's not frequently/ever delaying and relying on the brainpower of the chat to find lines for him.
Another point that I don't think has been focused on enough is how distracting it is to stream. While chat can occasionally suggest a better line, the vast majority of times the streamer's line is better than the suggestions. Although experienced streamers suffer less from this, one's play does degrade when trying to engage with chat. It's not an obvious conclusion whatsoever that streaming gives an overall advantage. I have considered streaming in the past, but I decided not to since it would make me play worse.
My last point is more of a pragmatic one. I love that people stream on twitch. Vintage is not a frequently played format and understanding why good players make the decisions they do is incredibly informative. I have seen several people state that they started playing the format because of the people who take the effort to stream it.
Magic Online is a terrible program to stream. Watch a Hearthstone stream to understand why. There are no fun animations. If you don't understand the specific cards being played it's very hard to tell what's going on. The game is not fast paced. There is way too much passing priority back and forth. World famous Magic players like LSV get <10% the number of viewers as popular Hearthstone streamers because of all of these problems.
IMO, the last thing we need is for WOTC to discourage streaming. A non-negligible amount of value from watching a stream is having someone suggest a play and have the streamer critique it while considering other plays. If you don't allow this, even fewer people are going to watch Magic on Twitch. Moreover, as Steve has mentioned, this outside help rule is unenforceable. Instead of streaming for everyone's benefit, you can just jump on a Skype call with your friends.
I don't disagree with any of the above, but it seems that if outside assistance were relegated to the unpaid queues, with no collaboration allowed in the tournaments with real stakes on the line, that would serve the interest of the streamers, the broader community, while at the same time maintaining the integrity of the tournament.