In my view, the majority of so-called photo tours are based on nothing more than 'reheated' tourist itineraries, and are labeled as 'photo tours' just because a photographer is leading them. Sure, let's label them whatever encourages people to take them, but these are not really photo tours.
My take on what makes a photo tour a real photo experience is much narrower. The real thing requires weeks (if not months) of research, and on site contacts, to offer enthusiatic (and demanding) photographers unusal locations and itineraries. Yes, some of these itineraries may often resemble those offered to regular tourists, but will differ in certain locations, differ in the amount of time spent at these locations, and certainly differ as to when (dates and time of day) these locations are visited.
A particular egregious example of a 'reheated' tourist itinerary is the ubiquitous photo tour which lists the popular Pushkar fair as main destination. It's absolute nonsense for serious photographers to time their stay in the town of Pushkar at the peak of the fair because it'll be full of tourists, the real camel trading occurs almost a week before the fair's announced schedule, hotels are more expensive at the height of the fair, and so on. If the idea of photographing a solitary dopey camel trader left with his final unsold scrawny camel (not to mention the gaggle of tourist-photographers who invariably will intrude in your viewfinder) excites you, go right ahead.
Another thing: photography is essentially a lonely activity, and being in a group photographing the same subject matter lemming-wise dilutes the thrill and satisfaction of photography. Many of these photo tours have participants who photograph whatever the tour leader photographs, who probably have no faith in their own visual abilities (aka 'eye) and rely on the leader to 'see' for them. I suspect these photographers return home, happy with their photographs just because they look like those of the leader!