[byoung2]

in fact it would be a (relatively) simple additional theme style that could co-exist with the existing PHP themes

In the process of adding a templating system to Wordpress you would come across many instances where you'd wish that instead of having to bother with structures like:

  <?php 
    if ( have_posts() ) : while ( have_posts() ) : the_post(); ?>
      ...add posts to an array, then assign to template...

The developers had just used an object model that let you do something like:

  $smarty->assign('POSTS',Post::getRecent(10));

And then access them in the template like this:

  {{foreach from=$POSTS item=post name=posts}}
    <h2>{{$post->title|truncate}}</h2>
    <p>{{$post->content}}</p>
    {{$post->url->permalink}}
  {{/foreach}}