All kids need all skills to read

ALL knowledge and skills essential to reading are essential for ALL learners. Absolutely every proficient reader must master all of the following:

a. Phonemic awareness: hearing the separate sounds and syllables in words and words in sentences;
b. Alphabetic principle: knowing which sounds go with which letters; using knowledge of which sounds go with which letters to sound out or decode words;
c. Fluency: reading words and connected text quickly and accurately;
d. Vocabulary: knowing the meanings of words;
e. Comprehension: making sense of text.

Every “school” of reading instruction agrees on these five, whether the schools are Direct Instruction or constructivist (whole language and balance literacy).
However, direct instruction makes certain that every child masters every skill. Direct instruction leaves nothing to chance.
On the other hand, constructivist theory lets the child “discover” these five skills. Consequently, some children will discover them all; some will discover some of them; some may not discover any of them.
In short, learning is too important to be left to chance.