Most discourse about A Song of Ice and Fire is oriented towards speculation rather than analysis. That is, towards conjecture about the events of future books, rather than the evaluation or interpretation of the the themes, personalities, and structures found in the text. Such an orientation is to be expected for an unfinished work, especially a popular unfinished work of genre fiction. But though ASoIaF will, in all likelihood, not be canonized as a literary classic, the five released volumes are rich with complex and compelling themes, characters, and ideas. It seems a shame that, though so much attention is devoted to these books, so little is devoted to seriously evaluating and interpreting them.
One need only take a brief look through any ASoIaF forum to see that discussions of theories and predictions far outnumber discussions of theme and significance. When themes are discussed, they are usually introduced as a way to support or refute a particular theory. Even the classic videos of Preston Jacobs, who has an exceptionally deep understanding of George R. R. Martin's work and the underlying themes of Ice & Fire, are overwhelmingly oriented towards his (somewhat outlandish) theories. It is easy to see why speculative discussions of the books dominate interpretive ones: ASoIaF is unfinished, full of mysteries that beg to be resolved; it is popular, thanks largely to its TV adaptation, and most people do not care much for literary criticism; and it is a work of genre fiction, doubly so because its criticism of fantasy tropes means that it is both of and about the fantasy genre. These books are unlikely to be studied by many serious literary critics, and they are an endless source of interesting theories and speculation. But though theorizing about secret identities and grand master plans is thoroughly entertaining, and there is nothing wrong with entertainment, ASoIaF has the potential to be much more. Its themes run deep, its characters are incredibly intricate, there are hundreds of motifs and symbols to be investigated, and near every significant event has a hidden or double meaning. There is clearly meaning and significance to be found here. GRRM usually sets up complex and comprehensive explorations of topics, rather than putting forward a single clear message (the exception, of course, being his overarching and near-absolute condemnation of war). The themes and characters of A Song of Ice and Fire deserve to seen and evaluated for their significance, rather than serving as simple fodder for speculation.
It is, to some extent, necessary to speculate when analyzing ASoIaF. The text exists in an unresolved state. Events of thematic significance are yet to occur, character-defining decisions are yet to be made, and the full structure of the text has not been unveiled. We will never, for instance, be able to evaluate the significance of the Others until we know more about them, and we will never know who Brienne really is until we see precisely how she responds to Stoneheart's ultimatum. Furthermore, the revelations of the final two novels will surely call for reinterpretations of some of the events of the first five, placing every current interpretation on potentially shaky ground. Some characters and plotlines may be regarded as completed or unlikely to be recontextualized, but most are clearly incomplete, and none are completely safe. Sandor Clegane's story seems to have come to a nice conclusion (though the identity of 'The Hound' still has a role to play), but even long dead characters like Ned and Rhaegar are the subject of important unresolved mysteries. Any analysis that may reasonably be rendered obsolete by the events of The Winds of Winter and A Dream of Spring is, implicitly or explicitly, speculative. This is not necessarily a bad thing—what can reasonably be predicted about the upcoming volumes probably should be included in our analyses, to the extent that it contributes to a deeper, fuller, more complete understanding of the narrative as a whole. Of course, different people have different definitions of 'reasonable', but such diversity of thought ought to be welcomed.
It's important to note that the character of ASoIaF speculation, and therefore a portion of the character of ASoIaF analysis, is determined by the fact that the author is alive and (hopefully) writing. A work that will definitively never be finished can be taken for what it is, with 'speculation' about what would happen next being little more than extrapolation from the text. But predicting what will happen in a work still in progress means predicting what an author will write in the future, a process that strays off the page and into the real world. Predicting The Winds of Winter as accurately as possible means studying as many of George R.R. Martin's interviews, blog posts, notes, drafts, and past works as possible. Determining the most likely direction for the story requires studying not only the text, but also the behavior and beliefs of a real man in the real world. Interpretations that are seemingly valid when considering only the published novels, like the idea that Coldhands is Benjen Stark, may be shot down by extratextual materials (in Coldhands' case, all it took was two letters in the margins of an old draft). The only reason why external or 'non-canon' evidence should lead to an interpretation of the main narrative being deemed unacceptable is because we have strong reason to suspect future books, which will be regarded as 'canon', will contradict it. As long as GRRM is fit enough to punch letters into WordStar, every word he says or writes will be a subject for speculation about his future writing, which will inevitably creep into the realm of ASoIaF literary criticism.
If tragic circumstances extinguish our expectation that there will ever be more canon ASoIaF material, however, the character of our analyses will need to change. If the text we have becomes all we will ever have, we will be free to evaluate it for what it is, not what it may become. If A Dance with Dragons goes down as the final novel in the series, there will be no real reason not to take Coldhands to be Benjen, if one believes it is supported by the text. GRRM's words may still serve as guidance or inspiration for the study of his work, but in the absence of his exclusive and limitless power to add to the text itself, readers will not need to pay him, or anyone else, any heed.
For now, though, we are left to examine a yet-to-be-finished work, not a finished or never-to-be-finished one. If we wish to extract the literary meaning from the pages of A Song of Ice and Fire, we must do so with the uncertainty of speculation hanging nagging at our backs and the shadow of George R. R. Martin looming over our heads. But I believe we will be justly rewarded for our work with a richer understanding of this most captivating work of literature.