Steam does that, the VOIP client in games is provided by steam, not the game. So really an impulse reactor VOIP client, not a demigod one.
In any case SUCH a missing feature. AT LEAST improve text-based communications. I mean right now communications is pretty shitty in-game. Make text-based communication colors better, more persistent, i mean in wacraft 3 it was pretty decent, in demigod you didnt even match a 5 year old game's text-based communication goodies
Font, color, and how long it stays on the screen is everything.