Please could we have a 'Convert Blocks' feature, that does exactly the same as 'Convert Pages' but for Blocks.
Currently, if you refactor a block type in code and rename it to something else, the existing blocks are effectively lost and will need to be recreated using the new block type.
This could probably be done directly in the DB but as there is already a feature that does this for pages it makes sense to extend this functionality to blocks.