The following concerns me, "Who is active on meta?". Do opinions, expressed by upvotes represent the entire population of Stack Exchange? For starters 701 pages of users on meta vs 9794 users on SO.
I speak out of own experience, that I couldn't (and still can't after asking one question) upvote answers I find valuable.
So who wants to upvote, and can't at the moment? People that are active on a Q&A site, have valid opinions about it, but aren't active on meta yet. They find argumentations they agree with, but can't upvote, but can't post a duplicate question/discussion either.
As a small experiment, I suggest that everybody who feels this way (and can't upvote!) favorites this question instead. This might somehow give an indication of how valid this statement is?
A possible solution, as mentioned here (again, which I can't upvote), is to allow more privileges on meta, based on priviliges gained on other SE sites. I would also make a meta account automatically whenever you join any SE site, to lower the threshold of participating in meta.
Ofcourse I know the privilege to upvote takes only 15 reputation, that's 2 people that agree with your proposal/discussion. Yet, as a good example, my previous question shows that that isn't always evident. Answering other questions isn't trivial (or desired) for a new meta user that simply wants to vote on his opinion. Bottomline, it should be easier for non-meta users to vote.
I realize this question is somewhat controversial, as it criticizes meta (that's you guys!), but I hope it will be given a good chance.