It never breaks formula (except for the grand finale which lasts two episodes), nor does the plot ever ascend "Big evil man must be defeated! Because he's evil!", if that's what you're asking. The shows' merits are located completely within the character interaction/development and the fights. If that doesn't do it for you, it's probably best you stop torturing yourself and watch something else.
That said, one tip for enjoying PreCure: do not, I say, DO NOT marathon a PreCure series (or any other year-long, formulaic kids' show, for that matter). These shows last about a year and are made with that in mind. They are not made to be watched fully within two weeks. It's best your limit yourself to one or two episodes a day.