From the documentation:
"Currently, you can only edit the name of your saved filter. If you want to edit the attributes in the saved filter, you’ll need to create a new one and delete the existing."
What?
A filter is a JQL string. All you have to do is show us the JQL string and let us edit it. There's an entire field for description that no one uses (though they should use to capture the JQL query that defines the filter). Instead, you let us define filters that we then cannot see the definition of. How is this even remotely acceptable?
Do you type your code into a file, feed it to a compiler, and then never expect to see your code again? If you find a bug, do you write your code from scratch again?
Also, the issues screen lets you define and save filters. But there is no way to apply a saved filter from the issues screen; instead, you have to go to the list screen. I cannot even; how can you be smart enough to turn on a computer and not understand what is wrong with this?
Finally: from the filter management screen, I can delete or copy a filter. But since I can't edit a filter, all I can change about the copy is its name. Why would I ever want one filter to have two names? How does this even make sense to anyone on the planet?
I mean this quite seriously: what the **** is wrong with you? How can you mess up something so utterly simple and basic?