Barlow WAS more suited to Iced Earth, but since he left the music has become more melodic, progressive and adventurous as a whole. IMO Barlow suits Iced earth a lot more in the minds of more hard core fans for the simple reason that he is more a part of the history of the band, as well as being the first really worthy vocalist they had. That "history" had to be created, and needed time to sink in - the simple truth is that most people find some sort of positive vindication in familiarity (like hard core maiden fans who wish Paul Dianno had never left the band, or to a lesser extent people who actually like AcDc's newer material) they want to hear a familiar voice, or style of music, (or chorus hook) that they associate either with good memories (ie. nostalgia), a period of the band that they liked (possibly even because of the frame of mind they were in when they "got into" it), or even just the previous chorus.
I don't like Owens because he is more technical - singing higher in itself does make for a more technical vocalist - Barlow, IMO is at least a more technically knowledgable vocalist than Owens (I have a book I ordered 4 years ago from the UK where both are interviewed, and its obvious that Barlow has a far greater working technical knowledge than Owens, who is really just a natural and has no idea how he sings like he does). I like Owens for his emotional intensity and his phrasing rather - and his natural talent. To me Owens sings with a lot of committment and emotion, its just that he is often given stuff to sing which is more "flashy" than Barlow, because he can do more with his voice range-wise than Barlow can so Schaffer was obviously playing to that.
Shane reminded me that when Owens joined Iced Earth, Schaffer said that his was the voice he had heard in his head ever since he had started writing songs for Iced Earth. Weird that he's gone from that to kicking Owens out of the band to get their previous singer back, who's voice he apparently regarded as being less suitable for the bands music? Just doesn't sit right to me and I think there may be something more to this.
I'm not Barlow bashing btw, he is indeed an awesome singer.