Season 6 opens with Beckett agreeing to marry Castle giving him an insight into what parenting would look like when a dying man drops a baby in their care however a new job for Beckett strains the whole drama.
"Get a Clue," at least with its Case of the Week, had a fun enough element to it - as does any instance where Castle over-imagines a far noisier and far-out method to the madness.
The fact that even Fillion sometimes has to stretch beyond his normal limits to keep all the pieces in place can be attributed to the fact that Castle is many different shows, many of them half-assed.
It may not have been anything earth-shattering, but it got the job done, and it felt like a classic old-school Castle episode, and that's enough of a cause for celebration, really, in and of itself.