As a cynical writer who loathes romance this was the one I was dreading. They would have to blow me out of the water to impress me with the Reid subplot I knew was coming. Did they do that? No, but they certainly came close. The relationship certainly was different as they promised from the normal Hollywood trash I've come to so despise. The power of having Reid hear "I love you" for the first time was incredible.
On the other hand I fear CM is sacrificing good writing for gore and shock value. This is powerful every now and then - look at season 2, all those well written psychological unsubs and then BAM, they hit you with the gore of Frank; but too often and the show becomes typecast and very boring. I don't remember what episode, but I'm reminded of the cop who begged the BAU for help a few years ago, saying "What, my bodies aren't covered in peanut butter so it's not interesting enough?" or something to that effect. The writers would do well to remember their old stories.