I'd like to see this functionality as well. Seems like a simple one to add. I just don't want to drop columns in the target DB. I only want to add the new columns from the source

Just adding missing fields is the feature I miss BIG time! For example: we have 1000 tables database. Production version is 10 years old. New version of those tables have many fields dropped. But I do not want to drop those fileds in the production because they contain data. It is a DATA LOSS! It should be a HIGH PRIORITY to make this tool data-loss safe.