I'm not sure why the OP is worried at 11800 miles. There's a possibility OP won't even own the vehicle when/if the waterpump fails. I think it should be mentioned that only the FWD based engines have the horrible waterpump design that OP is worried about. This includes FWD Ecoboosts as well, last I heard.
My previous job had 2 explorers with the 3.5 in their fleet. One went almost 300k before the waterpump had enough. The other was at 255k when they got rid of it, without a waterpump failure. These are vehicles that get around 50-60k a year put on them and only get oil changes and air filters. The oil used was always the "house brand" conventional at the independent muffler shop that was contracted to do all passenger car oil changes with the company.
I don't see a plethora of Ford vehicles with the 3.5 sitting on the side of the road. At 11800 I'd worry as much about this as I would a timing belt on a car with 11800. Can it fail? Yes. Will it fail in the near future? The chances are not high enough to worry about right now.