What proof do you want? We DO have the official information that the big ones indeed pay more, whether we want to believe it or not is a whole different discussion, but you build your argument on a hypothetical idea that EBU has been lying to us all these years about the big ones actually being the biggest funders. Now, I'm not believing in all EBU does or say, but until any contrary information and actual proof has been given all we can rely on is the info we got right now.
Well, we know that fees have been risen for 2013 in general, exactly how much for each broadcaster we don't know, but if the rise have been proportional then there would be no actual change to the biggest funders list in proportion to the others.
I wouldn't argue that the final brings the highest viewing numbers, but what do you mean? That all countries with large populations should be directly qualified then because of potential viewing numbers? I mean Sweden has more viewers than many bigger countries in this, so that's not even accurate that large population = big viewing numbers.
As for the competition, it's more beneficial to present your entry twice than just once, and again Turkey managed good positions that most countries can only dream of 3/4 years with juries, so I don't really see the problem here? Also, if we're on the subject of viewing numbers, it's obvious better for EBU and the broadcasters if as many as possible would watch the semis aswell and not skip them to only watch the final, so more countries in semis will also lead to higher viewing numbers for them aswell.
Bottom line = skip the Big 5 system or make it a rolling schedule where the year's highest funders will be directly qualified (maybe in one year Turkey is, another France etc.).