"Its starts in the place appropriate to the name” Well it does not even do that really. I would not call the place where it starts Worcester. It's a bit like the famous Ryanair airports. Its just a bit disappointing when you see the advertising and think ‘great, a run through Worcester’ and when you click through you find its anything but.
I appreciate the sentiment behind your first sentence, although a lot of places manage to get marathons or halfs through their city centres. Worcester is a place that is desperate to promote itself and a genuine city marathon or half marathon would be a way of doing that. In fact in a city as small as Worcester it could include a bit of countryside as well, as Coventry's does.