People donate to casters, as they like them personally, if they would want to donate to the tournaments or the players they could choose to do so.
Your second suggestion would kill open streaming and is a really bad idea in general.
That's why I don't like the second option.
Re: the first option: I feel like you didn't read my whole idea. There will be no more possibility for "normal" viewers/people to contribute to prize pool. The casters will pay a part of their revenue into the prize pool.
Why? It is simple: AoE casters can only get money if there are players that deliver great games. The game can only grow if there are casters giving high quality casting. They somehwat depend on each other (casters more on the players than the other way around).
So players should get a little of that money, I feel.
I love open streaming and I think it should always be open spectating as well.
I am only talking about tournaments here, not about donating/revenue in general.