In January of 2015 this question was raised as well. The suggestion from the Atlassian Team member was to reduce the number of characters.
This is a classic answer from a vendor to a user.....change the way you operate to conform with our software limitations :-)
Seriously, there is a need to name the JIRA Issues in a hierarchy so that they can easily be grouped so that related JIRA Issues can be presented on a backlog board in a logical work flow.
We are running version 7.3.9 and it appears that the 50 character limitation has not been changed....correct ?
Are there any plans to increase the character limit on Order By or has this become a parameter that can be modified ?