I'd like to see some more detailed analytics available in the charts and on the Home page.
Regarding the Home page, it would be nice to have Click-Through-Ratio in the table in addition to the Impressions and Clicks.
Regarding the charts on the Analytics page, I'd like to be able to compare two or more ads on the same chart, so that I can potentially A/B test two different ad creatives based on CTR.
It would also be nice to be able to select a particular ad and see CTR broken down for each zone in which that ad is shown.
For example, if I have one zone above a blog post, and one zone below a blog post, it would be nice to be able to show the same ad in both of those zones, but then be able to compare CTR for the zones to see where the ad is performing best. The way I see it at the moment, the only way I can compare the performance of an ad in two different zones is by creating two ads with the same creative to show in the two different zones, which soon pushes up the number of ads I'm dealing with.
If the advanced chart breakdown and comparison features could be offered in the Pro version, I think that would be fair, but I also think that at least a basic CTR figure should be given for each ad in the free version, even if it's just an extra column in the Home page table.