A couple of big features in this release include inline maps, where AutoMapper no longer requires you to call
CreateMap for new maps. I had resisted this idea (and even took out the
Mapper.DynamicMap feature) because I saw these dynamic maps as a bit dangerous. One of the original design guidelines was configuration validation, to make sure I didn't screw up a map.
It's bit obvious in hindsight, but I can easily support inline maps with validation by simply validating the single map on first map. You can get the safety of mapping validation with the convenience of inline map creation.