This is something that's actually been raised by writer P.S. Griffin over at our sister site, TV For The Rest of Us, in her recent Supernatural reviews. We know that Sam won't stop researching about the MOC and helping Dean based on the episode descriptions. But P.S.' theory is Sam will start adopting witchcraft, especially after seeing the MOC go away when Dean was changed to a 14 year old in "About a Boy."
Do you think the writers would go there? Take a page from Buffy and do a "Dark Willow" storyline for Sam? Will this be like the intended story for season three, where Sam saves Dean but at the cost of his own descent into extreme darkness? Do you like the idea of Sam trying dark spells and becoming very powerful with magic?
I'm not sure how I feel. I love the idea of Sam going darkside, but would that be a case of Rinse, Lather, Repeat? I wonder if this carries on with Carver's question of who is the real monster. As long as it's not lame like Lester, I might be on board for this.