FYI, sea salt is the same as any salt, salt is salt and it all came from the sea at sometime, there is no other place for it to come from. Mined salt came from salt deposited years ago from the sea, do some research on it and you'll find sea salt doesn't taste any different than Morton salt.
I believe SC is right the difference isn't sea salt, it's other additives that have gone into their new fries that change the taste. I quit using salt on most of my food years ago as it isn't good for the human body to have too much sodium. I instead season most of my foods with pepper. Wendy's is not noted for having food that is good for the person eating it. They also have gone through a big shake up selling off the Arby's line which they had acquired recently and are moving back to the former corporate home here in Dublin Ohio just outside of Columbus.
BK is my choice too and I usually have the chicken tendergrilled sandwich on wheat ciabatta bread and apple fries and a diet. If I'm going to splurge and eat beef I go with Hardee's Angus thickburger, worse for you than many other big sandwiches, but they taste really good. I usually tell them light on the condiments too as they put way too much on their sandwiches, it just runs off when you go to bite into them.
BK has also recently went through a big shake up and they rousted a bunch of dead corporate weight and are in the process of redoing their menu and trying to put emphasis on fresh food prepared in each location, not packaged and shipped to each store. I have an inside track on this as I know the owners and managers of 5 store in my area.
Mc Ds, I will not even set foot in there. Any food that doesn't deteriorate and degrade as food does has way too many chemicals in it for me to eat. Look at this youtube video about McDs 4 year old fries and cheeseburger:
http://www.youtube.com/watch?v=4IGtDPG4UfI