Right now, if you're making significant changes to an existing cube, the only way to verify that you haven't broken something is to actually do a build.
I'd like a Verify or Validate button, next to the Build button, that would do the initial steps of the build process and then stop. For example, determine if the metadata in the table can actually be retrieved from the underlying data source. Or checking datatype mismatches in existing joins. And so on. Just leave out the last step where you actually retrieve the full data set and then build the cube.
This would save time during the development process.