When selecting "Validate" for a beastmode it would be nice to have a preview presented at the bottom of the window pane. Then you can see if it is behaving as intended with columns used in the beastmode next to the outcome to compare. It would also be nice to see a more in-depth error as to why it did not validate.
Having a "Convert" button in dataflows would be great for switching from one dataflow to another. For example, a MySQL dataflow to a Magic ETL.
Connector Version Identifier or Notification
It would be great to have the version of the connector displayed in the overview tab of a dataset to make sure it is always up to date or to have a notification when it needs to be updated.