However, is what I've done wrong in any way? Have I breached any aesthetic or technical high grounds?
I would really like to hear some discussion about how people feel about this.
My 2 small-monetary-denominations:
If you use the photos as part of a travelogue to convince people to visit the place, then in a way you have lied to them about what it looks like, and it's wrong. But if you're making art (in other words, pictures just for people to enjoy looking at, with no implied promise of "reality"), then anything you do to it is perfectly fine.
I actually did something vaguely similar to an image of mine awhile back:(click here for link)