As of, completing the game and going to the 30th floor. I haven't defeated the hidden boss yet.
So these are my thoughts after playing to this point...
Oh, and I tried to avoid spoilers.
I'll get through the "bad" stuff first.
The main problems I noticed were:
1, there isn't much story this time. Of course, Etrian Odyssey isn't the most story-based game out there, but there still isn't much story or development for the final boss and an important story character.
2. For some reason, there were very few events in the 2nd half of the dungeons. In the 1st half, there was practically an event for every dead end and room, but it is the opposite in the 2nd half, with empty rooms... with nothing inside and dead ends that are just dead ends.
And it's not that much of a problem, but I wish the NPC that temporarily join you had artworks for the battle, like in Etrian Odyssey 4.
Oh, and not enough lolis.
Okay, so got that out of the way.
Other than those points, it was your usual Etrian Odyssey.
Character Customization - Needless to say, better than ever. You can change hair and eye color to anything in RGB and skin to various colors. You can also add voices.
Maps - Stratum 6 is pretty hell, that's for sure. It's not as crazy as Etrian Odyssey 3's Dark Zone + Holes + Spinning, but along with terribly scary enemies all around, it can even get stressful. Awesome.
Aside from that, Stratum 2 uses map hazards. Stratum 3 has damage floors. Stratum 4 has teleportation. Stratum 5 has floating (moves in 1 direction until a wall is hit).
Difficulty - Boss-wise, the last one I really had a problem with was Stratum 2. After that, you unlock your Second Names, giving you much more options. Aside from that, the Bosses for 3, 4, 5 Stratum were just not really that strong. In fact, the regular enemies for the 2nd half of 5 and all of 6 are far more difficult. Heck, as far as Stratum 6 enemies go, I gamed over, went back to where I was, and then game overed in the first battle. Twice. That's how nasty the enemies in 6 are.
Classes, Music - Not much to say. Good old, good old.
DLC - Especially considering the huge amount of DLC, with some using up part of the map, it was a great improvement to announce from the start "Hey, these are all the DLC we are doing, so don't worry about DLC hell again". And the DLC are just extra music, graphics, and the usual (and not needed) grinding quests.
So aside from some story-related, extra stuff, I don't really have any complaints. They did make a few adventures, but all in all, it's good.
It's kinda like Pokemon. Is the new Pokemon game good? It's Pokemon. Is the new Etrian Odyssey good? It's Etrian Odyssey.