We're sailing the same boat. Your direction is our direction as well. The entire period since the SP1 release was mostly spent in some API reference improvement along with the other help improvements - new topics, fixes, etc.
Actually, things have not gone quite as we planned and there is still work to be done, but we'll do it.
As for this interim release, we've put some efforts into documenting the major r.a.d.grid
classes: RadGrid, GridTableView, GridColumn. The improvements are not limited to them, but these were the significant ones.
The course is taken and we'll make it to the end, just give us some time! :)
Meanwhile, please report any properties/methods/whatever you need and you have found undocumented or badly documented - they will be included or improved immediately.