I really, really like Heydon’s framing of inclusive design: yes, it covers accessibility, but it’s more than that, and it’s subtly different to universal design.
He also includes some tips which read like design principles to me:
- Involve code early
- Respect conventions
- Don’t be exact
- Enforce simplicity
Come to think of it, they’re really good design principles in that they are all reversible i.e. you could imagine the polar opposites being design principles elsewhere.