Zivush - 4:20 am on Aug 7, 2012 (gmt 0)

why doesn't the Google Adsense team offer all their publishers the ability to define the size of the ad

That is The question.
I think they genuinely want ads look like ads for the the vast majority of publishers mainly to protect their advertisers from invalid clicks.
When it comes to brands and big sites, the picture is changed and other factors start to play.
[[OK, moved this part of the discussion to Adsense forum hoping that Adsensers will read it]]

[edited by: Zivush at 5:02 am (utc) on Aug 7, 2012]