My last 2 trips have been short (3 park days each trip). The first one (about 15 months ago, so before FPP) we didn't park hop. I figured it was such a short trip it wasn;t worth the extra money. I really regretted it. I knew I could have added it while on the trip, but when it's halfway through the 2nd day of a 3 day trip, it's REALLY not worth the money, so we just didn't PH. We had no children with us and really wished we could go to Epcot or MK every evening, but we couldn't. For us, while we enjoy DHS, it's really a 3/4 day park. And we didn't even go to AK. No way could we spend a whole day there.
Earlier this month, DS (20) and I went, again for 3 park days. I paid up front for the park hoppers, I learned from last year... We hopped every day and were able to see A LOT more this way. Not all the nighttime shows were on every night we were there, but we still saw them all. Heck, we watched Fantasmic! and the MSEP the same night! We were able to take a short break at the resort every day too. We went to AM and PM EMH's when available, utilized FPP and got many additional FPP's each day, at the original park and the park we hopped to. We didn't eat any TS, all CS, because DS isn't interested in food that much (he picks quantity over quality! LOL!). We had a great trip that wouldn't have been nearly as fun or full if we hadn't hopped. I've learned my lesson, park hoppers are worth every penny for us, even on shorter trips, or maybe they're even more important on short trips!