Although others don't see the 'dark cloud', as a long time user of Rust it has definitely put me off pushing for it too hard at work. That said, Diesel and Serde are now the only big libs that require nightly, but this is due to them relying on syntax extensions which are going to be stabilized in the next release. So if I were to start a new microservice using those libs it would be ready to go on stable in a few weeks time, which is super exciting. The only other thing would be async IO. Tokio is making big strides in that direction - not sure what the time-frame is on being able to use it on a server nicely though.