Since text-mode is very programming-like, I'd like to see the ability to comment-out text mode code as well as simple line-by-line comments.
This would require a way to do "start comments" and "end comments" (to comment out large blocks) as well as a way to do a simple one-line comment.
This would let me document why I did what I did, or test a new bit of code while leaving the old bit in there in case things go wrong.
This would apply to all text mode areas: filters, groups, fields, etc.