It was a bold move commiting to Astro right from the start. Medium and small maps have a high likelihood of galley access, although you could argue that the mapmaker wanted to give teams a fresh challenge from SGOTM5.
When LC challenged us with his proposal on how to get Astronomy in the BC years we reasoned a bit about it and finally decided that it could be a competitive strategy even if all AIs could be reached by Galleys. Maybe not vs direct galley access, but definitely if culture bridges would be required.