YUIeditor version 3.5 is not supported

The YUI library may be at a 3.5 release, but the editor is not.
The page on http://yuilibrary.com/yui/utilities/ indicates the Editor component is still in Beta.

At the top of http://yuilibrary.com/yui/docs/editor/ it also says:

The current release of the Rich Text Editor for YUI 3 is the base utility layers that provide a foundation on which you can create an Editor. This version of Editor does not contain a GUI of any kind.

We'd essentially have to build the whole GUI and all toolbars/buttons/commands ourselves, a task too big for this module.
Once they release a more complete editor, we can have another look at supporting it.