A good and succinct account of the simple view of reading is here. Its basic idea is that reading consists of two elements, decoding, which it says is based on phonics, and comprehension, a time-honoured but obscure word that means understanding.
The need for understanding is self-evident, and I welcome current research into building it up. JM Carroll and others, Developing Language and Literacy (Wiley, 2011) is an important account of this work.
The first reason the simple view is too simple lies in its equation of decoding with phonics. In order to decode in English, we need both phonics and a systematic approach to the occasions on which phonics does not work. It is not enough to say that there are irregular or sight words, as this leaves the learner with no systematic way of dealing with them, or of using the partial information conveyed by the letters that make them up.
We have, as far as I can find, no systematic research on the teaching of irregularity in English, and yet it is an issue that is obvious to everyone who has ever learned to read. For phonics proponents, it is an Achilles' heel that has allowed the guessing game people to make fun of them, establish themselves in academic positions by means of factions, and impose nonsense on the population. For the guessing game "school of thought", it is a fact that they have misinterpreted and abused in equal measure to sustain an approach that has no basis whatever in research or practice.
What needs to be done? There are several options.
1. Careful case studies of people with serious difficulties.
2. Controlled trials. It is never possible to use the medical model in education for one overriding and essential reason - you cannot blind the teacher in the same way as you can a doctor. It is one thing to make two identical white pills, one with an ingredient and one without. It is another to expect a person to teach without knowing what he or she is doing (or supposed to be doing...)
3. Linguistic analysis. Irregularity in English is a fact, capable of objective observation and analysis without the need for experiment. It is therefore capable of investigation via inductive reasoning, provided that a model of spelling is accepted as a starting point.
What is not an option is to continue as we are, with two competing sets of half-truths. Or, more accurately, one three-quarter truth and one piece of sophisticated rubbish.
Update. The idea that word reading (aka decoding) and comprehension are the most important elements to reading appears true. However, they are not the only elements. Reading also includes the grouping of words into phrases and sentences, and the right pattern of intonation and emphasis that is needed to bring out the full meaning of an English sentence. Quick, accurate word identification is essential to phrasing (See Perera, K, PhD, U Manchester c1989) but the idea of picking words with in a sentence for particular emphasis isn't always evident to people who have learned to read as English native speakers. These are good reasons for continuing to hear children read aloud, from demanding texts as well as from easy ones, well past the initial stages of learning to read.