Here's an example of what I would consider the best scenario for people who tour like us. Like a lot of other people, we like to visit one park at opening, ride as long as lines are short and the park isn't too crowded, take a break in the middle of the day, and then visit a second park in the late afternoon or evening.
Assuming no changes in tiering and keeping the limit of 3 in advance, I would like to be able, for example, to book one FP at MK in the morning, and 2 at DHS later in the day. Then, I would like using the one at MK to trigger the additional FP that I could use and rebook the rest of the day while still holding my 2 evening FPs at DHS.
I think this would encourage hopping because you wouldn't have to wait until you arrive at the second park, when FPs for the most popular attractions will be gone or very limited, to get FPs to use there.