Interesting, and I feel for him. That said - to me Redemption never really sounded like Fates Warning at all, but Ray absolutely sounded like Ray.
I think Tom could sound like Tom and no one, or almost no one, would confuse Redemption for Evergrey. It would only sound better, but Tom sounding like himself is pretty awesome.
I'm not saying that Nick's not being truthful in that post, but I wonder if he actually knew about Tom singing differently before he delivered the vocals for the last album. In the ProgPower interview, he mentioned Tom working on them on his own and he was a little nervous because he wasn't hearing anything and it was taking a while. (Total paraphrase and I can get the actual interview early January just to make sure). Maybe Tom did this on his and Nick kind of had to live with it, and they had those lengthy conversations after the fact. Or maybe not - that's complete speculation on my part.