On the Tuilagi debate, it's easy to pigeon hole someone, but his prime strengths remain power in a straight line and heavy defence. He's also more of an off loader than a passer. At 13 you're more defensively exposed and time and again we've seen his tendency to rush out of the line.
All of these point to 12 where can be much more involved in the game, causing damage in the heavy traffic, which is surely to the most benefit of any team he plays in. It might mean that his attacking role changes to consistently breaking the gain line by 2 or 3 metres and tying in lots of defenders, rather than the eye catching breaks into open field, but to be honest in space I'd rather see the superior speed and ball skills of JJ or Daly.