If the devs said no, then we should just keep asking. As a developer I know there is not a good reason to avoid putting this into the game. There are ways of implementing it which would indeed be a burden on development and servers, but there are also ways which would not.

One way that comes to mind is that some games integrate other voice services simply to ensure platform barriers are not an issue. For example, since Mumble was brought up, Mumble is open source and fairly easy to enable an embedded client. Devs could bridge services like Mumble, PSN, Steam VoIP through SDKs that already exist without developing a whole voice system. If individuals could login to a voice channel shared by their friends, parties, alliances, free companies.. it would be a huge bonus.

I don't see this as an optional feature or a thing that people should accept being missing. Similarly what's up with the development on gilseller filters. How can you program the rest of this game and not realize how basic things like these two features are? They're not that complicated.. do you need help lol?