Make more fields case insensative.
It makes less sense that you have to type 'Berlin' and can't do 'berlin' or 'BERLIN' or whatever.
However this is more than enabling the 'ignore case' filter in Search API as the Facets need to have lowercase values, not labels; and further the value from the URL needs to also 'ignore case' - presently lots of people using the API (or maybe bookmarks) are using 'Berlin' and this can't break when it becomes 'berlin.