I grant you that there are plenty of times it seems Stu is trying to sound like Barlow. However, that may not be by his own choice. Remember this is Jon's band, and what he says, goes. I thought it was awfully interesting how Stu, on the Live in Ancient Kourion release, literally spoke to the crowd like he was Barlow ("brothers and sisters!").
However, when I saw the Block-era Iced Earth live, Stu didn't do that, and vocally, put his own spin on some of the songs, where appropriate. So while I see your point, I think the cause of that is possibly not Stu, but Jon asking that of him.
if you disagree with what I said about Stu, there's nothing I can do about that. Opinions and all that, it is what it is.
But I'm not so sure the focus of your ire should be on Stu completely. There may be other influences at play, such as Jon. just something else to consider.