Try to generally increase line-height in design.css:
/* the document */
div.dokuwiki div.page {
margin: 4px 2em 0 1em;
text-align: justify;
line-height: 1.5em;
}
And on the other hand to decrease line-height of footnote markers in the text:
div.dokuwiki a.fn_top {
vertical-align: super;
font-size: 80%;
line-height: 1em;
}
These changes should probably go into the default template of DokuWiki. It really doesn't look good with different line-heights only because of footnotes.