I completely agree. Unfortunately, what I've seen more than once is that mgmt (or even someone from the rank-and-file) sees / experiences a new tool like Slack (or Campfire, or Hangouts, or...) and says "hey, great new tool we should use!" and that's the 'decision'. No thought given to how async comms biases development when developers are spread world-wide.

I gripe because I am a US left-coaster who works with a team that is increasingly based in Western Europe. By simply deciding to rely on Slack, they have essentially cut me from development conversations other than the weekly live session.