It would be good to have a standard checklist of edge cases to handle with plaintext protocol design. Anyone know of one?

I'm thinking along the lines of:

1. Control characters

2. Whitespace normalization

3. Newline normalization

4. Options for compression

5. Escaping characters significant to the protocol

6. Encoding characters outside of the normal character range

7. Dealing with ambiguous characters (not really an issue with strict ASCII)

8. Internationalization (which is intertwined with the previous items)

9. Dealing with invalid characters

I'm not saying plain text doesn't have its advantages, I'm just saying there are issues you need to consider.