Here are my own thoughts, so far as I've looked into it.
From Scripture it is very clear that the Spirit proceeds from the Father (St Jn 14. 26 & 15. 26), but there are arguments to be made that the Holy Spirit may also proceed from the Son (see again St Jn 15. 26a "I will send...") as well. The Roman Catholic Church has also argued that because all that is the Father's is also the Son's (St Jn 16. 15), then the procession of the Holy Spirit, which is the Father's, is also the Son's.
I've also heard some arguments about how in some of the Epistles it refers to Christ's spirit effectively, but I think that's immaterial to the question of procession of the Spirit. That's trinitarian, but procession is not.
Ultimately the summation there is that the Holy Spirit definitely proceeds from the Father, but also might proceed from the Son. In my view it's also something that's not necessarily answerable. So then what situations arise out of this with respect to the use/non-use of the filoque? If the Holy Spirit proceeds only from the Father and you omit it, you are correct. If you include it, you are incorrect. If the Holy Spirit indeed does proceed from both the Father and the Son and you omit it your position is true but incomplete and if you include it, you are correct.
That said, when the Nicene Creed was established, it was accepted, East and West, without the filioque. The addition of the filioque has never been received by the whole Church, even though its creation predates the great schism. By what authority was it added? Can a bishop change the ecumenical creeds? Can the Roman Catholic Church change it? Can the Episcopal Church of the United States? Can the Anglican Communion as a whole?
I would argue that none of those bodies have the authority to alter the creeds from what has been universally received. They have the authority to establish peculiar/particular creeds of their own, but they certainly wouldn't carry the same authority as the Nicene Creed.
The second point alone about the authority is my main reason for omitting the creed, though I find, given the uncertainty, that being partly right is better than being partly wrong.