Boolean wishlist search?

Yes you can do that, assuming the wishlist is for title or keyword (or maybe actor; can't remember if you can apply modifiers to actors).

(these are from memory, so may not be exactly word perfect; as assume you're doing a title wishlist, keyword would work just the same. The difference is keyword searches titles and discription while title just searches series & episode title)

Go to create new wishlist
select keyword
type in the first keyword "this"
select add additional keyword
type in the second keyword "that"
navigate to the right and then down to the list of two keywords. To exclude "that" highlight it and press thumbs down.

That'll add a minus sign in front of the word and that wishlist won't match or record any programs with that excluded word in the searched text.

If you'd entered thumbs up the keyword would be put in parenthesis meaning "OR", while keywords with no modifier are treated as AND. (Note: The OR applies only between the keywords you've placed in parenthesis); so "(this)" "(that)" would mean either or both would match, but "this" "(that)" means both need to be there because you provided no alternate choice for "that"

 

You can do this with Titles, Keywords and Actors. Not Categories.