When the account name is different from the user name for authentication, ask the user, whether the email for authenticarion shall be inserted as ORGANIZER;SENT-BY=…
When the CN after ORGANIZER or ATTENDEE is the same as the mailto: address, do not insert CN. This has no added valie and just increases the traffic.
Obtain from the user its name and use it as CN for the ORGANIZER, or get the name from the principal-url (if not already done), perhaps as its displayname. The CN is used layer by rhe server ro send emails and it appears as display-name. So with proper CN the email will lool nicer.
I understand the single address book per account issue and agree with keeping it as is. However, it would be nice to have the capability of copying an account so if there are numerous books it’s not necessary to enter there login information over and over. This may be an Android limitation, but the ability to change the name of the account would also be nice.