If one is tired of Castle's antics at this point then I'm not sure what that person is looking for in this show. I don't think Rick is going to change his interests any time soon. As Jax pointed out the writers clearly want to make him a fun character and a balance to Kate's more serious but playful side. Nice Alexis and Castle moments in the episode again.
Does anyone think that they are going to reveal that Ashley or Alexis has been cheating on each other? For some reason I am getting that impression, especially with Alexis' inability to properly deal with the situation. It might be just me...so toss it out if you feel like...but she's not exactly been at ease with her current situation so I wouldn't be surprised if the writers decided to do something wacky with her character. It would be something out of character and potentially interesting to see how Castle deals with it...but I'm most likely reaching.