These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Not only that, but many plot points introduced in the film's opening are dropped almost immediately after. Dragons returning, the death of the king and the implications of a war on the horizon all seem like they'd be major plot points later but are never brought up again.
Many Earthsea fans will tell you that the series has quite a few characters who deserve a movie more than Arren.