Im not going to propose a mobile/ajax-htmltheme (as others proposed), 
but some small tweaks which make the lookandfeel a bit more like 
'nowadays' imho.
These are small fixes which improve tablet/smartphone viewing a bit, and 
give everything a bit more 'zen' to it.

html/style.css
==============

 body.body { 
  font-family: sans-serif, Arial, Helvetica;
  background: url('logo.big.jpg') no-repeat 44px 20px;
  color: #333;
+  margin: 2.0em;
 } 

+pre{
+ white-space: pre-wrap;       /* css-3 */ 
+ white-space: -moz-pre-wrap;  /* Mozilla, since 1999 */
+ white-space: -pre-wrap;      /* Opera 4-6 */
+ white-space: -o-pre-wrap;    /* Opera 7 */
+ word-wrap: break-word;       /* Internet Explorer 5.5+ */
+ padding:1.0em;
+}

+button.button-big{
+  width:140px;
+  height:70px;
+  font-size:20px; 
+} 


 table.body {
   border: 0;
   padding: 0;
+  border-spacing: 1.0em;
   border-collapse: separate;
 }


html/issue.item.html
====================
<textarea tal:content="request/form/@note/value | default"
            name="@note" wrap="soft" rows="5" cols="80"></textarea>

(I changed the wrap="hard" to wrap="soft", and in combination with the 
<pre> stylesheet-settings, it wont break long urls, because then they 
become unclickable, and also it will prevent the 'search'-field 
dissappearing from the screen which happened with long content)

The edit button
===============
Attached is my issue.item.html which initally hides the form-fields 
behind a big Edit-button. I had to do this because else issues looked 
too complex for my nontech-clients. After using it for almost a year, I 
can say Im really used to it, and I think the experience is much more 
calmer now. Think about it: first information, then editing-forms :)