The thing about this game is that, I think, there's the possibility for a wide spectrum of how "powerful" your character is. . .
Some players might not be very good at picking a strong skill tree. Some players might miss a lot of the "optional" skill books, set equipment, etc. Some players might not make good use of the enchanting and charming features.
If you're a real 'power player' and get a really strong build, by level 30 you're rather god-like, it's true.
The devs have to make it so that someone playing on normal, who might not leverage all the optional and hidden bonus items real well, can still complete the game. I think that's why you are finding it so easy for you - you've ended up with a very, very strong build.
By the way, have you done the "Mighty Morphin Power Rangers" encounter yet (that's my own name, btw - it's a group of rogue dragon-slayers you can fight in an optional encounter)? I honestly found them to be one of the hardest encounters in the game - mostly because there's five of them and most of them use very powerful ranged attacks against you (magic and bows). It's certainly winnable, but I found it to be very much a challenge.
I found with most of my characters, that when I first entered the first flying fortress, it was pretty hard, but pretty quickly got easier as I continued to level up.