That would be very helpful, because God is not He or She. But we can't really change languages, there's a lot of stuff being invented both in German and French to avoid using the general masculine and address both male and female, but it doesn't really work. So, it won't really work to create a pronoun for God. Maybe, it's the best always to use the word God instead of pronouns in English. As long as we don't have another revelation, there won't be any new first person ...
Deliberate innovations to language are difficult and awkward. And often not recommended. Not all-out impossible, but generally languages develop things somewhat organically.
I wish the unique pronoun already existed. It would make sense given the uniqueness of God.
Years ago when I still thought I would write fantasy novels or something, I toyed with what pronoun I would use for the god of the characters. I was toying with O as in "O" being the pronoun, but didn't quite figure out what the declension would be -- would it end up looking like I, Me, Mine, or He, Him, His, She, Her Hers -- You, Your, Yours, We Us, Ours, It, Its, It -- not wanting to base it too obviously on any of them and didn't get far.
Closest I came was "O, Om, Ors" so it would be kind of evenly split amongst "I, Him, Hers" in similarity.
Anything unusual or new just won't flow in a sentence. Using God as God's own pronoun when you speak of God to pay attention to God and give God God's due -- becomes a tongue twister too...