Following the initiative of VDVsx, let's start a thread to get (constructive) feedback about the whole Contacts/IM experience on N9/N950: questions, remarks, bugs...
Feature requests are accepted too, but we now have limited resources on Nokia side to implement them... The good thing? All our middleware is open source (see [1])! Which means you can too contribute the features you'd like to see.

The disclaimer is the same as for the email support thread: although I work for Nokia, this is not an official support channel, and the people who'll take time to answer you will do it on their spare time.

[1] https://gitorious.org/qtcontacts-tracker/