So I got Etrian Odyssey IV yesterday since it's on sale again for $15 on the eShop.
So far, it seems okay, but there's some minor issues such as Poison and other effects being a little too common in the 2nd "Maze" (I think that's what they're called here), and this is early on as far as I can tell. The strength meter for the FOEs seems to lie a little bit as well. Even if they're blue meaning they should be weak and easy to defeat, I almost got wiped by them (Especially that one that poisons and damages a full line every time.)
Poison damage is always based on what afflicted it in the first place, and I do agree that it occurs a bit more than it should. Thankfully it's the second maze and not the second floor as was the case in the original DS game, but you're right that the second maze is still a bit early.
For FOEs, blue doesn't necessarily mean "weak", but more that you're of appropriate level to beat them if you approach them with a solid strategy, while yellow means they'll rough you up some and red means NOPE.
The engine in this game also seems a bit more lacking than the one in Untold. You can't Run, Floor Jump nor Speed up battles which is a tad disappointing. Grinding also takes way longer because of it. I've yet to see a healing spring, nor get access to purchasing any items that refill TP too. The skill trees in this game kinda suck, possibly more than Untold's, but I grimoired the annoying to unlock skills there, so I can't really judge..
Untold also came after IV and as such, it's naturally going to have more stuff going for it.
As with the rest of the games, how effective each class's skillset is depends largely on what you try to do with them as well as how they mesh with the rest of your party.
Anyway, issues aside, I just got to the 2nd Maze, my team is all level 25, but since every freaking battle is a pain to get through, I'm guessing I'm a bit underlevelled. More grinding needed I guess..
I don't remember what level my party was at in the second maze, but things on the third floor of the maze are a complete pain regardless unless you hit them with status ailments.