I think the execution wasn't super thought out. These are three characters who are moving in different directions. Harley and Ivy are villains, and while Catwoman really is best as a villain, she's in the process of being molded into more of a reluctant hero because of her relationship with Bruce. So for the three of them to all be in a title together, it just doesn't really stick together once you get past that initial "wacky roommate" phase (which was pretty much the first arc).
Not to mention you have a writer who, instead of trying to develop the characters or explore their personalities, is going back to cheap tricks like mindwipes and ex-boyfriend adventures and goddamn does that shit get old fast.