Elizabeth Schussler Fiorenza is, to coin a phrase, awesome. Brain the size of the universe, lovely person, inspiring writer and speaker, fearless in the face of patriarchal power in the RCC (makes Bishops quake, she's so much smarter than most of them and knows more theology) - and yes, an academic Feminist Theologian. She was one of the key thinkers in my journey out of the RCC and in calling myself a feminist. I met her a few times in the 80's when she was a visiting speaker over here in the glory days of UK feminist theology (before anglican women could be ordained - i.e. tamed and incorporated into the patriarchal church structures!)
What she did (many years since I was involved in feminist theology) is to coin a term that helped American white christian feminists dialogue with American black christian feminists. We (WCFs) were constantly talking about patriarchy - we kept being pulled up by BCF who pointed to our position of power in relation to Black men (American BCFs began to develop something called Womanist Theology). I had a journal article rejected because the Womanist theologian peer reviewer didn't think I had taken that perspective into account :( Well no, because I was white working class British and that's another whole layer of power structures to think about!
So ESF has never, to my knowledge, ever suggested that we should replace the word patriarchy with kyriarchy - but she simply coined a phrase which seemed more descriptive of the complexity of interlocking societal power structures we all operate within. She was looking to make common ground with the womanist theologians I think - and they were (are?) a powerful voice in the American academic christian feminist / womanist scene (in the 80's / early 90's anyway).
So the term has to be seen in it's context, an academic word, coined within a very specific context. My view is that it can be useful in some situations to use it, like most words, in particular when in academic dialogue with women who do not fall into the 'white privileged' category, either through race or class.