hive external table needing write access
Partially answering my own question:
Indeed it seems not to be resolved by hive at this moment. But here is an interesting fact: hive does not require write access to the files themselves, but only to the folder. For example, you could have a folder with permissions 777, but the files within it, which are accessed by hive, can stay read-only, e.g. 644.
If you require write access to hdfs files givehadoop dfs -chmod 777 /folder name
this means your giving all access permissions to that particular file.
I don't have a solution to this, but as a workaround I've discovered that
CREATE TEMPORARY EXTERNAL TABLE
works without write permissions, the difference being the table (but not the underlying data) will disappear after your session.