I made a mod for servers which shows an icon above someone's head when they talk in teamspeak.
https://forum.blockland.us/index.php?topic=281964.0
It requires the server to be in the teamspeak channel and any client who wants the icon to appear, to have their LAN name set to the same thing as their teamspeak name. So the server can identify them.
It's nowhere near as good as an integrated system. But-

In my experience, voicechat w/blockland was good. Hearing someone's reaction when you nail them with a jeep is awesome. :D And generally being able to communicate easier was just- good.
As far as annoying people go, they're annoying in whatever method of communication you use. Whether it's voice chat or text chat.
Administration options.
can talk on join?
automatically allow some people to talk based on blid list?
automatically allow admins to talk?
administrators can "announce" to talk over others?
volume adjustments depending on distance between players?
admins can adjust the volume of some players?
talking rooms?
talking teams? integration with slayer?
allow clients to limit max volume they hear?(to prevent ear rape)