Monsters in Beowulf

As usual, the essay topic 'Monsters in Beowulf' was a popular choice, and after the tutorial discussions I was musing on the subject of Grendel and Grendel's mother and their general 'monstrosity', and how that's often interpreted by modern audiences. The recent Zemeckis film is a case in point, where Grendel is presented as a humanoid figure, and the aural torture he suffers at the hands of the noisy and inconsiderate inhabitants of Heorot is designed to ensure that we, the audience, feel some sympathy - or at least understand - his behaviour. Similarly, his mother is perhaps not like other women in that she's a golden version of Angelina Jolie, but once again, she is not presented to us in a visually monstrous incarnation, and is given the opportunity to express her grief at the loss of her child. While this nods to the complexity of the original poem, at the same time it seems to speak to the modern concern with motive, with the distaste for presenting evil as simply evil, but rather as something that can be explained or given a rationale. But I wonder how far a contemporary audience would necessarily have had similar sympathies? Would they, like the sculptors I discovered in my searching of the dark hinterlands of the web here http://www.grendelsmother.org/, have felt sorry for poor old Grendel's mother for being nameless? How far are we imposing modern expectations and interpretations on the monsters of the poem?