Problem: The Answer UI shows, prominently, the answer box at the bottom of a question, regardless if the user has permissions (Edit permissions on the object) to answer it or not.
Reproduction:
See:

This is as an unprivileged user (approved, but not given edit perms otherwise) viewing the question.

When attempting to enter an answer, anyway, the expected error modal is presented.

Potential solutions:

1. If the user has no permissions to answer, hide the "Answer" field under "New Answer"; show a box with "You cannot answer this question" in its place.
2. Make the "Show n Comments/Add a Comment" control more prominent, perhaps as a button control rather than a link. See this under UIExamples for a potential example.
3. Make the comment entry field expanded by default, rather than hidden behind the "Add a Comment"/"Show n Comments" control.

A quick and dirty mockup of solutions 1 and 2 are shown below.

As always, if any further information is needed, feel free to ask. I'd submit a Task, but I'm still new here. :)
(edit: fixed the mockup, the button was riding a border with no margin. oops)