Just to clarify, we won’t have a single “official” simulation platform. We intend to support as many as we can based on technical capability to use a simulator and resources to maintain a connection.
However, we will have a default simulator that will be used in tutorials and quick start guides, etc. My opinion is that licensing reasons make CARLA the best option here. @esteve has also made good arguments for why CARLA is technically the best option. As always, we are open to other opinions. In the long-run, what we want most is a healthy ecosystem of simulators that cover each other’s weaknesses.