Note that if you just use a regular Maya Area Light instead of the Arnold Ai Area Light, you will have all the control attributes under the Arnold tab that you would for an Ai Area Light if you selected the Quad shape (apart from the 'Light Shape' attribute). See the Quad Light Shape topic for details of how the Arnold Ai Area Light works with the Quad shape selected.
The Lights page has more detail about the controls. In addition to honoring the standard Maya light attributes, the Attribute Editor will also show the following attributes under the Arnold group:
Ai Area Light attributes