Personally, I 'd love more than anything to choreograph the battle scenes. A lot of complaints from the European martial arts community towards medieval/fantasy films deal with some rather silly conventions the film makers seem loath to abandon in their depiction of sword combat.
I'd want to do it the proper way, e.g. arrows will
not penetrate plate armour (unless perhaps Elven arrows), swords will
not be clashed together edge-on-edge, cavalry charges will
not be conducted without benefit of shields and lances (and not by the Gondorians, who were almost exclusively infantry-based at that point), the list goes on.
I can just imagine Aragorn executing the murder-stroke with Anduril...
