Hi,
1- I think should be able to right click on the address to edit key or label information. (It took me a while to figure out the double click to edit) 2- I think when adding an address on address book, could have an option to add custom fields. We could add, rename and delete the fields.
Yes I think these are good suggestions. (2) will require some changes to the core, but I've also proposed before that being able to attach arbitrary metadata to transactions/addresses would be useful.
Closing this. Part 1 has been implemented already.
Adding additional information on an address does not sound useful to me as addresses are not meant to be reused. (adding information on a transaction may be useful on the other hand... this is already what happens in the case of a payment request)