Of course the point obvious point here is that the thing that would make Christians more appealing in this scenario is their actual actions, not their beliefs. Those actions would be viewed as "good" for the simple reason that they are the naturally evolved human behavior possessed by most of us. If a majority of Christians started behaving like me, it wouldn't make me want to be a Christian, it would make me wonder why they had been so fucked up for so long.
The answer to that question would be, of course, belief in Christian superstitions, and the exhortations in those superstitions to force themselves on others.