The difficulty seems to have fallen a lot since the boss fight with
om nom nom Xi Wangmu in Ikebukuro
Hopefully it picks back up. I actually found it pretty challenging up to that point with the tutorial dungeon probably being the hardest.
Hate to break it to you, but it doesn't. It's insanely easy after the beginning. The last boss can be difficult depending on your path and experience with SMT, but the game doesn't go above normal difficulty from where you're at.
That is kind of disappointing. Guess it is due to the new fusion system. Don't get me wrong, it removes a lot of the tedium present in previous games but it also allows you to create teams that can handle any situation pretty early on thanks to the inheritance system. Still, I am having a lot of fun with the game and don't expect that to stop.