this may be due to the fact that Bean has 'better material' to play with in LOTR
1- temptation by the Ring - in the Council and especially on the mountain when he holds the ring.
2- a Death Scene - EVERY ACTOR WORTH HIS SALT CRIES OUT FOR A DECENT DEEATH SCENE!!!!!!!
Now for Viggo, his acting in LOTR is basically done through his 'emotion' - ie
1/ after gandalf falls - his shocked look as the arrows fly around him
2/ his view of lothlorien and the joy it holds for him
3/ the marvellous view as he walks towards the multitude of orcs after letting Frodo go
but to add to this - his acting in Bree, especially
1/ when he drags in frodo to his room - I know what hunts you!
2/ when he describes the nazgul and Sauron the Deceiver to the hobbits
is excellent.
I'm only dragged out of middle-earth occasionally by these 2 when their accents fail -
for aragorn - funnily enough at bree when he mentions Sauron the deceiver above - his voice drifts back to a mid atlantic accent
but boromir wins hands down as he cavorts back to his Sheffield accent when on Caradhras - we should take the road to my CITEH! (instead of city!!!)