Boaz Barak seems like a good person? Or even the tweet I linked to by Richard Ngo and Jacob Buckman

Why not find the stakeholders who do have sufficient incentives to allocate funding well; i.e., those who stand to benefit most from the decisions that are made?

Could you give me a concrete example? For many concerns it's impossible to reach them (eg longtermist ideas about the future) and for global health and development while it's possible (although I am slightly sceptical of the benefits)

I don't think that they won't be irrational. I think that the need to have a reputation would lead to them being more rational than the median voter. EA organisations will make mistakes. Voters too will make mistakes.

But only EA organisations will face public blowback for that and over time will have better processes for correcting those mistakes

this seems like a very good idea!

That is true, but I also do think that the symbolic value of doing it is very high. If you're a community that believes that the government should do [policy] it is not only good PR but also makes you understand your beliefs better if you also pursue that policy (to the extent that you can scale it down)

I'm not so sure. First if your goal is to influence the general public, I don't they they'd be very influenced by that. 

Second, even if you do use a journal's brand name (say Nature), it only works in the short run. The people who read it frequently  know about the change in management and would be (at least) a little sceptical about the new management. So its not entirely clear that you would be able to use the previous legitimacy.

And finally, whatever legitimacy existed could be destroyed with a few articles that were out of consensus with the previous journal. Perhaps someone more well versed in the sociology of academia would know better but I think that it wouldn't take very long for its reputation to change to the "weirdo journal" or anything else. 

My biggest concern though is that even if it worked and the previous two points were wrong, I don't think convincing academics is the best brand to buy. It would be more on the lines of getting famous people across various sections of society (actors, singers, sports players, politicians) to endorse EA or specific EA causes. So better would be Rihanna's or Ronaldo's brand just so that your reach is maximised. 

The first exception about AMCs not being effective is interesting. Do you have more resources on them?