A top clamp by itself won't change anything about the handling. It can't, because it doesn't change any of the geometry. So unless the clamp lets you use fat bars on an older bike, or offers you a handlebar position that the stock clamp doesn't (and that you actually use), they're just bling.
I disagree with you about the Tag T2 clamp, which is the one you had, being lower quality than the stock unit. The T2 is a simpler bit of work than the Tag Matrix, or other top tier clamps are, but still a very good, functional piece equipment. I had on on my '03, and it was fine.
Yeah that explains why it didnt help. But you know when you get something new your brain is tricked into noticing a difference even if there is none. And by the stock piece being better quality, not in the way that it is great, but the tag was nothing special. I sold it for almost what I paid for it so its a ded issue. I would rather spend on a complete set that will help the handling, and add some bling!
Edit; Also at the time I didnt know anything about offsets so the shop coulda sold me anything and said it was better. I wouldnt have known the difference. I am still learning about this stuff. I used to just get a bike and ride the crap outta it. Now I wanna know about proper set up.