Lightest way to control a field's markup So far I have used Display Suite to control the output of entities. This especially applied to node's fields which by default receive multiple wrappers (like field-items, field-item, zebras and such) which I don't need. Correct me if I'm wrong, but I would say that installing Display Suite only for that purpose is a big overhead. If you agree on that, what would then be the lightest way to get exactly the markup I want?
Yes I think Display Suite is quite an overhead just to control field markup. You could obviously overwrite the templates manually, but for a quicker solution there's the excellent Fences module

Fences is a an easy-to-use tool to specify an HTML element for each field. This element choice will propagate everywhere the field is used, such as teasers, RSS feeds and Views. You don't have to keep re-configuring the same HTML element over and over again every time you display the field.
Best of all, Fences provides leaner markup than Drupal 7 core! And can get rid of the extraneous classes too!

The difference in markup is huge. From
&lt;div class=&quot;field field-name-field-test field-type-text field-label-above&quot;&gt;
  &lt;div class=&quot;field-label&quot;&gt;Foobar field:&amp;nbsp;&lt;/div&gt;

  &lt;div class=&quot;field-items&quot;&gt;
    &lt;div class=&quot;field-item even&quot;&gt;Leaner markup means better front-end performance.&lt;/div&gt;
  &lt;/div&gt;
&lt;/div&gt;

to
&lt;h3 class=&quot;field-label&quot;&gt;Foobar field&lt;/h3&gt;

&lt;div class=&quot;field-foobar&quot;&gt;Leaner markup means better front-end performance.&lt;/div&gt;