Pay is quite variable among derm vs path and even derm vs derm and path vs path. Depends on your priorities.
There are derm-trained DPs who went to top 5 med schools/derm programs taking low-paying academic jobs because they want to be in academics.
There are derm-trained DPs taking DP path only corporate jobs, same job a path-trained DP could do.
There are path-trained people working for derm groups, etc...
If you want to maximize money, you could do that from any route. I went the path route and took a job doing surg path and derm for a private path group. It was the best starting offer of any DP fellow in my year that I know of, path or derm-trained, but I am obviously biased. It was the best job for me.
If you like pathology and want to practice surgpath in addition to DP, go through pathology. I don't think it's much harder to get DP through path, since ~1/2 of programs are in path departments. You just have to be 100% committed to getting a DP spot and work hard trying to do research/network. It may take a couple years/application cycles but it can be done for anyone.
If you like clinical dermatology and have the grades/scores, by all means do the derm route.
Personally, you couldn't pay me enough to do derm clinic. Boring and I hate outpatient medicine.