I doubt Mumble/Team Speak are ever going to be as popular as they were before. But boy do I wish they would.

- Native UI: everything happens instantly

- Lightweight client

- The ability to host your own server

Even initial setup difficulties had an upside. More often than not, those who weren't capable of properly setting things up also weren't the right fit to play seriously/competitively. Such little barriers were a great initial filter for toxic wannabes with short attention span.