There are actually two different Traditions of Dianics out there.
First of all there are those who follow the writings of Z Budapest who honor only the Goddess and totally reject the God. Practice in such groups is limited to females only and many of them are very much anti anything male. To me and to many others those like Z who reject the male aspect of Divinity are not truly Wiccans but rather Dianic Witches. In fact when Z started her Tradition she did not refer to it as Wicca either. http://dianic-wicca.com/dianic-wicca-tradition.html
The second Tradition is the McFarland Dianics. They honor both the God and the Goddess; although their emphasis is on the Goddess, and their covens have both male and female members. I would consider the McFarland Dianics to be Wiccan if they so decide to call themselves. You can read about their beliefs at http://www.mcfarlanddianic.org/faqs.php
You see the whole concept of Wicca is that the Divine presents itself in both male and female aspects. Wicca is and always has been a fertility religion and without both God and Goddess there can be no fertility. It is the relationship between the God and the Goddess that provides the energy that powers all of creation and brings life here on earth.
So, at least in my humble opinion, if you wish to believe only in the Goddess but omit the God entirely from your practices I would call myself perhaps Dianic Witch, or simply Goddess Worshiper rather than Dianic Wiccan.