AK is more than Pandora (which, admittedly, is my favorite thing at WDW much less AK). The opportunities to see an amazing variety of animals and enjoy unique food is outstanding. It also had the best coaster through 2021 in WDW. I agree that it isn't a full-day park, though. We usually use it as a split day (park/resort or AK+EP).
Whether you have seen the film or not, FoP is mesmerizing. Easily the best ride in all 4 parks. It's basically the exact opposite of Smuggler's Run...SR puts you 8 feet away from a 10 foot screen using the coolest spaceship in the world on a silly heist - FoP puts you 5 feet away from a massive multi-level screen in all directions and tries to make you feel alive in every sense of the word.
If you have to pick between visiting either DHS and AK at all, I'd recommend DHS based on your preferences. But since you can do both, I think AK offers enough great experiences, that it is worth doing both, even if you prefer DHS.