Hi Kai,
We made some revisions based on the last round of feedback we received from you. You'll see below we made changes to the basemap layer menu and the map overlays so that we can better call out some of the main functionalities of the site.
We placed the overlay options at the top because they are the priority menu options that give users the choice to turn on/off the individual layers to road networks, projects, local gov.,...and etc.
For basemap layers, we created an exapndable thumbnail pane so users are able to preview the basemap layers that are available. This gives users the ability to quickly view other options in the case that DigitalGlobe or Planet Labs don't have satellite imagery available.
Olaf has filled me in on the discussion you're having about using other satellite and drone imagery, so I understand that is something we'll have to think further about. The mockups below are designed to scale as we make further decisions about satellite imagery.
Let us know if you have additional questions. W'll be happy to jump on the phone to talk through anythign else in further detail.