Width of comments box could be increased in JComments template CSS: /components/com_jcomments/tpl/default/style.css:
#comments-form textarea {max-width: 400px !important;width: 350px;margin:0}
and
#comments-form .grippie {height:13px;display:block;overflow:hidden;color: #ccc;padding: 0;margin:0;border:1px solid #ddd;border-top-width:0;max-width: 400px !important;width: 350px;cursor:s-resize;background: #eee url(images/resize.gif) no-repeat right center}
Increase default width and maximum width values in these lines...
About number of comments pending approval... Such feature isn't available at this moment but in next version it might be implemented. Now we have only posibillity to display unpublished comments list in JComments Latest module (select mode "Show latest unpublished comments") but this mode made for administrators or users who have enough permissions to publish comments.