Hi Lars,
agree that "show definition" is nice, but if we need to copy the column names of a table we need to do "show definition" and then "export to sql" to get the column names or i generally use "generate select statement" or fire a sql statement like above.
Yes it finally depends on what you wanted to do after you get the output 
But still having an option like "describe" or "show" table should be nice to have in the sql editor and see the output.
Is it not planned in the further releases also?
Regards,
Krishna Tangudu