Various issues.
Serifs:
- Very few people actually have Linux Libertine, so the normal default header font is Times New Roman, which is a very plain font and throws people off.
- Georgia has much better looks, but totally wrong metrics (too large). Some way around the wrong metrics may make it usable.
Perhaps apply Wikimedia typography style guide?
https://design.wikimedia.org/style-guide/visual-style_typography.html