as the title say, it would be good if there is private chat with ppl in our friend list..here is some advantage of having private chat that i can think of now:
1) talk to them into joining our guild
2) asking them to change their leader hero for our benefit like quest
3) chat [ until now i never meet ppl in my friend list at world chat since there is too many channel ]
* hope dev team can reconsider this suggestion