Problem: AbuseFilters are a powerful tool to fight some cases of harassment. But the window used to edit AbuseFilters is ridiculously small. As a consequence, it's a chore to work on AbuseFilters, especially when working often on it.
Proposed solution: Make the AbuseFilter edit window larger by default (there is no valid reason for having a so small window), and make it resizable.
Who would benefit: Firstly, abusefilters editors; indirectly, all users subject to on-wiki harassment.