In regards to voice chat, it may be a nice option to implement in-game, but I don't see the majority of players using it, even if they have mics. I'm only basing this off of Steam games where voice chat is built in and only four to five out of twenty players will talk. And from Xbox Live, playing a non-FPS game, you may have three out of eight players willing to use their mics.
Obviously this would be for those people who feel like they have no chance to communicate in-game. If they for some reason don't use the feature, then S-E can't really be blamed for that.