The filoque would not need to change. The Eastern Rites would continue to use their variant of the Nicene Creed, and the Western Rite theirs. There is no "filoque" in the Apostle's Creed at all, yet both halves of the Church, Catholic and Orthodox, use it without damage to the faithful.
This is one of the distinctive differences between East and West, but it is not an excuse to keep sundered the Church that Christ made whole and called to be united.
But do you see....THAT is the point. The filioque is NOT correct. It is a SERIOUS doctrinal situation, that needs correcting. And that is just the drop in the barrel.