It does support rich text. However you need to know the formatting of Wiki's (for hyperlinks just type them in - hyperlinks ending in .gif .jpg .jpeg or .png are rendered as images, lists are preceded with multiples of 8 spaces).
What is really needed is a Wiki sandbox, so you can test out the Wiki features. Also if you give too much control (i.e. change fonts, sizes etc) you lose control of how it looks - Wiki's should have a consistent look and feel about them.