1) My earnings with a network compared to what I got with Adsense, where 300-600% higher.
2) 2 of 3 networks I`ve been in as head of recruitment then a recruiter then a Co-CEO. have had 10-20 licenses, written and from the game publishers, but you`re right the majority don`t have them.
3) Perhaps, I recently co-started a network and I already had contacts with 3-4 companies/sponsors before-hand so I now have only a few partners and a few sponsors for them.
4) YES, This is a feature all networks have and after having a channel I had in the past banned for that, and 15% of channels get their Adsense banned for that within 4months of starting to use Adsense.
If you get your Adsense banned for that you`ll never be able to make money on that account again :|
For your size of a channel branding deals wouldn`t be hard to get, it depends what network you go with,
I tweeted at you on twitter earlier and a few mins ago about a network