I expect certain things when I read a Stephanie Plum novel... I expect Stephanie to be awful at her job, I expect her to wreck or blow up at least one car, I expect her to love Morelli and be freaked out about commitment, I expect her to be in lust with Ranger and freaked out about that, I expect Granny to do and say some things that make me cringe, and I expect Lula to be Lula. Mostly, I expect to laugh and forget my life for a few hours.
This is not great literature. This is fun, ridiculous, escapism. If you are expecting more than that, you will likely be disappointed. I see that several reviewers have been unhappy with the last few books in the series. The books are written using a pretty obvious equation and expecting it to change now, twenty books in, is likely an effort in futility.
If JE writes another fifty Plum novels exactly like this one, I'll read them all, they'll make me laugh, and I'll happily look forward to the next one