I've never used Slack in a business context which leads to: what polish is missing that actually affects your use case? You mentioned mobile for instance but how are people using the mobile app while also being in an actionable position?
Not everyone is a programmer! I've had plenty of times when I was getting messages on my phone that mostly required informing/connecting the right people/departments. If I hadn't done it stuff would have eventually gotten done, but a lot later & with more misunderstandings and miscommunications.
