improvement
For those who've kept up with the Digimon Story games, this game is the best one, in my opinion. It is a definite improvement over the Moonlight/Sunburst's insane encounter rate, and there are more Digimon than in the first game.
Granted, if you didn't like the other games, you probably wouldn't like this one either.
What's different about this game? There's more story than in the first game (I never really finished the second to tell), and there's the addition of the Evolution Tree and Plates. In order to evolve into the Digimon you want, you first have to make sure that it's in the Tree; if it's not, then you have to find the plate (usually from random battles), fix it up, and put it in. For example, the Togemon plate is dropped by Tanemon early in the game.
Fixing up the plate is sort of like a required minigame. You have 3 tools -- putty, scraper, and cleaner -- to clean up the plate. Sometimes, there are also chunks of crystal (Crystal Bugs) growing on your plate, which need to be cleaned off with laser first. The whole plate needs to be done in approximately one minute. Luckily, if you don't finish repairing the plate, you don't lose it (unless you made too many mistakes). You just get a lower score. The higher the score, the more skills a Digimon can learn when in that form.
Most everything else is very similar to the previous games, I think. I'm really enjoying it, and it looks like it'll be up for 40 hours of gameplay, quests included.