I guess what they say about beauty being in the eye of the beholder is true, because I think the stock bracket ruined the look of the whole back end both from the side and the back.
I am actually of the exact opposite opinion of you. I think Triumph actually did a pretty decent job on the license plate bracket. The only thing I'd change would be to get rid of the little nubby bumper thing that sticks out. I give you credit for using your ingenuity to come up with an alternative idea, but to be honest I don't think it looks any better. But as Triumph says, "Go Your Own Way." Make it your own I always say. I'm glad you are happy with the results.