>>24692260Much more difficult in some senses, mainly due to a lot of changes to mechanics. There's less of a sense of permanent progression, since leveling is slower and you can get IQ skills as equippable items, but they always disappear at the end of the dungeon, leaving you at square one most of the time.
Also like
>>24692246 said, the game heavily pushes you towards recruiting Pokemon and using more mons than just your player and partner.
On the whole, I'd say that the game feels much, much more slanted towards the Mystery Dungeon elements than the previous games, which has both some good benefits and bad consequences. Personally I don't find it quite as fun or satisfying to play, but I'm still quite enjoying what there is to do.