I've posted before, you can see my theory here: http://www.whoisredjohn.com/See-a-theory-Red-John/4185
I've used Rosalind's description before, but lately I've been thinking why hasn't Jane himself taken it into consideration? He has boiled down his list of suspects to only seven suspects based on what? well definitely Rosalind's description is not one of them, otherwise Bertram wouldn't be on the list. So I can respect those who doubt Rosalind's description. But some folk say stuff that are downright nonsense, like it wasn't Red John who saved Jane in the second season finale, or that Red John is not a person but an organization, or Red John is Jane. If you're going to be skeptical of everything then there's no point in constructing theories, since there's no data to back your theory. There are some facts we cannot deny, like Red John being somehow connected to Visualize, or him being a charismatic leader.
Despite all this I still think it's Haffner. Think of the suspects in terms of a scale from the most expected to the least expected. My experience tells me it's always someone in the middle, someone most people wouldn't think of so that the show can preserve the element of surprise. On the other hand it shouldn't be disappointing either. The best choice for the middle suspect is Haffner. Just think of it for a moment. Think of the person Rosalind, Miriam, Rebbecca, and Lorelei fell for. Think of the charismatic leader who gave orders to Todd Johnson, Craig O'Laughlin, Timothy Carter, Jared Renfrew, Sheriff Hardy, and possibly Hardy's father. Think of all you know about what he's done. This blank image you've been imagining since the first season doing what he does, replace it one by one with the seven suspects. Trust your gut feeling, who's the guy that fits this image? For me it's Haffner. I challenge you to go through all this and still claim it's Partridge!