I think they're getting caught in a difficulty-spiral. I mean, did the Slime Pits really need to be made harder? Really? REALLY? No, they didn't. It was already a hard branch, and the Royal Jelly is going to forever remain one of the hardest monsters in the game, corridor or no corridor. It's still better to fight in a corridor, by the way, although it's fun to us the stairs to climb down, shoot spells at the Royal Jelly, and then climb back up before he reaches you.
Wanna know what needs fixing and difficulty tweaks? The fact that a lot of the mid-game uniques are heavily armored fighters who also cast spells. And by spells, I generally mean various bolts. That's not very interesting. Donald can stay, but Joseph and Frederick need to be changed or cut. And many of the early uniques are easy to kill once you've gained a few levels, but then give out a crazy amount of exp for their difficulty. Is Pikel really THAT dangerous? I think Grum gives out less exp, but Grum is far more challenging.
@Soapdreqm: AC and EV are uncapped. They can go as high as your stats, equipment, and skills will allow them to. 14 AC and 26 EV is actually pretty good, but keep on training Dodging and maybe raising Dex.
Nemelex actually replaces spells quite nicely, in most cases. For instance, you don't need to learn Abjuration because Decks of Summonings have you covered. Still, it's always good to know Butterflies and Intoxication, and Apportion is one of those spells that's surprisingly useful.