The following blurb was found in the The Sydney Morning Herald by Dan Mihm. The article hints at another reason why Townsend might have been let go.
The Sydney Morning Herald
Filming of the Lord of the Rings trilogy has had a setback, with the sacking of the Irish actor Stuart Townsend (Shooting Fish) just days after the cameras started rolling in New Zealand.
London’s Daily Telegraph reports that producers are negotiating with Viggo Mortensen and another actor to take over the role of Aragorn.
A publicist would not comment on the reason for Townsend’s departure, except to say that there had been “creative differences”. She denied that filming, which began in the hills around Wellington last week, was in disarray.
Insiders on the set said that Townsend was dismissed by director Peter Jackson after a problem with “director-actor creative chemistry”.
Townsend, 26, was widely regarded as being too young for the part of Aragorn. Mortensen is 41.