I like the automated aspect of the Textpattern comments form, except for how darn big the Message textarea is. Unfortunately, this is not something that can be remedied via CSS, since the form size is specified in the style attribute of the textarea itself, which trumps any styles declared further up the food chain. It is easy enough to fix, however.
Open up textile/publish/comment.php in your Textpattern installation directory, and head for line 183, which should look like
$textarea = '<textarea name="message" cols="1" rows="1" style="width:300px;height:250px" tabindex="4">'.htmlspecialchars($message).'</textarea>';
I changed the height attribute to a shorter 100px, and it looks much less intrusive.