I think there're two aspects where Alfred can improve:
1. Allow user to search for content in the files in a specific folder (i.e. before using 'in' function, user can assign a specific folder as the search scope)
2. Allow user to specify the file type for search. For example, search pdf only in a specific folder.
I understand that these functions can be implemented by making workflows, but it's hard for non technical person like me to create one. I wish that these would be built-in function or in the sample workflows.