"Good witches" go back a fair way. Consider "The Wizard of Oz" (published 1900), or Cinderella's "fairy godmother".
I think it would be fair to say that historically, both "witch" and "warlock" have negative connotations, but a lot of work has been put into rehabilitating the image of "witch" (particularly in the last few decades), whereas virtually no-one has ever tried to portray a sympathetic "warlock".