Lotsa fast banter and stylish direction will make some viewers dimly recall--as they are doubtlessly meant to--William Powell and Myrna Loy's late, great "Thin Man" movie series.
Yes, it is all kind of dopey and has that "been there/ done that" feel. But Fillion is so right for the part and carries the show so well that he makes the show more fun than it deserves for an otherwise by-the-book procedural.
Katic has the more thankless role, as the actress in this scenario inevitably does, but the necessary sparks fly when she and Fillion are on screen together swapping barbs, and hopefully as time goes on, she'll get more to do than play kindergarten teacher to Castle. How much you like the series will depend almost entirely on how you enjoy watching these two spar; for me, that was enough.
The problem is that in the pilot and an early episode, the crimes are nowhere as compelling as the characters. For a show like "Castle" that dares to launch a more classic version into an already saturated and tarted-up market, the murders have to be as complicated and compelling as the push-me-pull-you glances between the main characters, and so far, they just aren't.
I know this is going to come as a shock, but when the scene is designed around Kate, the show sags. By contrast, when Rick strolls into the room, the show perks up.