Rugby Challenge 2006 was made by Swordfish Studios, so didn't they use JLR as their "foundation". That was there problem in some ways that was their problem, they just copied it with better graphics, and the gameplay etc was dated (same problem with ALL Pro Football 2K8/ 2K5).
With no disrespect to either developer, I'd say that Rugby 08 is a better foundation than RL3 (not that either were that bad - RL3 was miles better than RL2). Gonna be very interesting to see some official gameplay vids over next few weeks to do some legit comparisons rather than screenshots