It would be nice if a path defaults to all paths in the index. For example, imagine I have a customers collections with the fields "firstName" and "lastName" and I want to create a search based on user's full name. Then I create a search index on these two fields. Now imagine I call this index "fullNameSearch". Then whenever the "fullNameSearch" index is used, I want to run it on all paths. Instead of me having to specify the paths, it would be nice if the path defaults to all fields used in the index.

Another example where this would come in handy is when using autocomplete. Autocomplete works only on one path, plus you have to explicitly specify the autocomplete indexed field in the index. So why not read this path from the index and use it as the default?