I would say that one MAY carefully look past the language and look to the idea. The point that is made by such terms as "persons," "essence," "substance," etc., is that of how God is one and three (Triune). These terms are used to distinguish heresy from orthodoxy. By saying that God is one (essence), we acknowledge the truth of monotheism and the roots found in Old Testament. This is against those who would say that the Father, Son and Holy Spirit are three gods (tritheism). God is strictly one being and remains one always. That is monotheism and the Christian God.
That they are equal in essence and each fully God is against those who would say that one (such as Christ) is less divine, or inferior in divine nature, than another (Arianism, semi-Arianism, etc.). That we acknowledge Christ as the second "person" AND fully human (+the previous statements) is to say that it was God who was on the cross and not a mirage or Gnostic vision.
Also, we acknowledge His incarnation because He is God even before birth (Adoptionism, Nestorianism, etc.). We say that Christ is a separate person than the Father, not to confuse, but to say that Christ is not a third god, nor is he the same person as the Father. To say he is the same person is to say the Father died (and Jesus would be talking to Himself in prayer) and to say that he was another deity would be against the witness of Scripture and human reason.
The key revolves around "procession/begetting" and "personhood," especially the way in which God is three-in-one and how God remains one, without being separated. Understand the reason and logic behind the philosophical language and you will understand the truth and message of the Trinity. That is what kept me from becoming a Muslim (and I came mighty close). I apologize for the length of this post, but I hope this helps a bit...
Prayers and petitions,
Alexius
