Theorizing Adaptation

Beginning to Theorize Adaptation. This is a topic that I have never really put much thought into until reading author Hutcheon’s statements on the matter. I, as Stram argues on page three, feel that the written word, literature specifically, is “axiomatically superior over any adaptation of it because of its seniority as an art form”. To whit this implies what Stram calls “iconophobia”, or  “a suspicion of the visual”. Implying that when we use visuals to tell a story we can cheat and use these visuals to relay the narrative we wish instead of the one that took great pains to build in our minds through words. As such, any attempt to move thoughts or ideas from text to film, or theater, would result in total destruction of the original art. I had not originally considered the idea that adaptation could make a positive contribution to the story telling. I believed that after reading a story like Lord of the Rings or Harry Potter, yes I know they are not works of literary genius, when experiencing them in film the editing of the text would leave only the message that could be best told through the medium of film and thus would lose the plot of the story for shock and awe.

However, after reading the text, I have revised this opinion. Sort of. There are several things to address here. First, is there an understood license that while adapting a novel, or other works of text, that there can be no alteration or changes to the meaning of the story? Must the story be told in the exact words and visuals conjured up through the words of the text? There is one problem here. Here on page eight, this idea of the ‘mind space’ or “res cogitans” is discussed in detail in regards video games, another form of adapting media. As the author here points out that,” [visuals] cannot easily adapt… what novels can portray so well: the “res cogitans,” the space of the mind.” What images my mind produces in reading the story, the ‘set’ shall we say, will most probably be different from the one you have produced in your mind. This is axiomatically a problem. So there must be a different visual produced by everyone. One reason why I dislike movie versions of books, are for example, the producer is not seeing Rivendale in the way I did while reading the novel.
The idea of adaptations from book to film or vice versa is fraught with all kinds of problems. But the idea behind it, the intellectually thought, is something I never before considered and evidently there is a lot to it.
So my question lay here. 
1. Is there an expectation that a story must not be altered as the medium is altered? 
2. Should we expect that novels are always at there best when the imagination of the reader is left to build the story in their own mind, or can someone else, like a produce of a film, do a credible job of this for us.