While I agree the thumbnail can look bad if scaled way down (like from 200px to 50px) it is not as bad if the sizes of the thumbnail on the products page and the product detail page are closer (say within 25 or 50px of eachother). The solution if you have a large difference is of course just as the mod shows.
To move the description under the rest of the details, simply edit product.tpl, cut and paste this chunk of code where you want it to appear:
Code:
{if $product.fulldescr ne ""}{$product.fulldescr}{else}{$product.descr}{/if}
And for future reference, you don't need to post the whole mod, a link will suffice
