Typeface for dyslexics

It seems to be a common misconception that target readerships are separated groups (e.g. of non-dyslectics vs. dyslectics, visually impaired vs. normal vision people ...).

Unless you want to produce and use multiple versions of each sign, notice, book, etc. a typeface that performs better for a minority but worse for the majority is useless.

That logic is totally flawed. Why bother making wheelchair ramps if most people can walk up stairs? In fact, why bother making wheelchairs at all? Why bother doing anything if it only helps a minority? What about braille?

Function never trumps aesthetics. Aesthetics is about appropriate design. Not pretty design.

Function should trump everything - aesthetics included (and aesthetics is not about appropriate design from a functionality point of view) - otherwise we're just in the business of gilding lilies.