To say the Holy Spirit proceeds from the Father and the Son, is to attempt to change the very nature of God as he has revealed himself - the Orthodox belief that God is three persons and yet one God. The addition of the filioque is to confuse and turn upside down this revelation. This is not just an argument about words, of semantics; it comes to the very heart of who God is. It is this fundamental Christian truth that the Creed was promulgated to protect!
To this day, the Orthodox Church stands firm on the use of the Creed in its original form as declared at the first three Ecumenical Councils of the undivided Church. It is interesting that some Protestant Churches have, in more recent times, expressed the Creed in its original form (without the filioque) as an alternative or preferred form. The debate still rages between the Roman and Orthodox Churches concerning the filioque. It was this inclusion into the Creed that had so much bearing upon the eventual separation of the Roman Church 1054 AD, and, sadly, it is its continual use that proves to be such a major obstacle in any talks of reunion.
Not what we "consider" the "early form", it is actually the original Nicene Creed as adopted by the Councils. That's just a fact, Harley. What the Latin Church and virtually all Protestants say, because you got it from the Latin Church, is a later version designed to address Arianism. For centuries it was condemned but eventually the Franks forced its acceptance on the Western Church. The Pope today, of course, uses the original form when praying with Orthodox hierarchs and people. As I understand it, the original Greek form is also used by the Latin Church for catechesis.