Missing service: realtime message broker (for IoT)
I think Azure has a wide range of services that somewhat come near to a global, scalable, reliable, realtime bidirectional message broker aiming at real low latency, but all miss something to be "the solution" for Azure customers.
I know there is Azure IoT, but it is very asymmetric toward data ingestion. SignalR is not that much scalable. Event Hub is one direction only, etc.
They all aim (or at least try to) at very low latency, have a wide range of supported platforms, seem to be scalable.
I think Azure has the infrastructure but is missing the service. And I am not speaking of installing Kafka on Azure VMs, I mean a true pay-per-use we-care-of-everything service.