Not trying to be a jerk Nicky, but I can't help thinking back to your previous posts and bikes. It's your money and your decision of course, but I get the impression you are never satisfied after getting the bike you swore you really wanted. I seem to remember one you got rid of because of a paint defect that MIGHT happen. So I'll answer your question with one of my own: Do you have any idea what you really want? Asking everyone on the site to make the decision for you isn't the answer. You need to seriously address your motivations and be honest with yourself about what it is you want in a motorcycle. Do you just want to look cool and chase the latest trends, or do you want a motorcycle that performs well and is enjoyable to ride? Most of the "trends" started by the bike show crowd are not conducive to a better performing and handling motorcycle. Twenty foot long choppers, ape hanger bars that stretch you out so far you can't really control the bike, monstrous rear tires that hurt turning and handling, huge front wheels that remind me of those old bicycles from over a hundred years ago, and let's not forget those lovely tinted clear coat over bare metal paint jobs. Harley copied that from the show circuit and I think most of us know how that turned out.
If you truly love your 2015 Street Glide, and only you know if that is really true, I'd suggest you leave it alone and if you just have to have the latest trendy thing then hire a custom bike builder to build one for you from scratch. Hopefully he will have it finished before that trend fades away and a new one takes its' place.
JMHO - Jerry