If Arianism, viewing Jesus as a 'divine' but subordinate figure (like today's Jehovahs Witnesses), wins out then it would have major impacts on Islam, assuming Mohammad or someone like him comes out of the desert with a new creed.
On the one hand, OTLs Islam accepts Jesus as a Prophet, special, but well lower than God, which makes one suspect theyre closer to Arianism than Nicene Christianity; on the other Islam views Trinitarian Christianity as veering towards polytheism. OTL, we can say "there is but one God, he just has three persons/faces/aspects". Arianism muddles the picture a lot. One God and another 'divine being'!?!? That sure looks like polytheism to me, and Im sure it looks even more like that to a Moslem.