The patristic evidence is simply the sacred deposit of faith. It is not the issue of popularity; in fact, much of the patristic literature was written when the Arianism was the majority faith.
All I know about Arianism is that it denied the divinity of Christ, and it was kinda sorta related to Gnosticism. I didn't know it was ever a majority "faith".
When I said "popularity", I think I was mainly referring to within the Church. I know I have been told that any individual, or even any individual Father, could have and did think and write things that are now considered wrong. However, if enough of the clergy got together and agreed that something was right, then it could be declared either infallible, or dogma, doctrine, or discipline. (I think maybe you taught me that. :) Anyway, I was just saying that because I have a different view of the authority of the Magisterium, that I thought that not only is any one man capable of error, but that also any one group of men is also capable of error.