It's important to realize Compass began at a time when IE6 was still a concern for designers. You only need to look through the documentation and you'll see numerous IE6 and 7 hacks are still present in its codebase. While there still may be a small percentage actually using IE6 and 7, this shows that Compass is perhaps coming to the end of its usefulness.
In my opinion, the rapid adoption of Flexbox and SVG coupled with the decreasing need for vendor prefixing will reduce the need for Compass drastically in 2016-2017. This might seem sad to some people, but I think we should be happy. That means we no longer need as many hacks to make our designs. That means we're moving in the right direction as an industry.