I play the game on nightmare difficulty and at some points I lowered the difficulty for a moment (for killing Zagan, for example).
And the game was never too easy for me, except a few parts are not that hard as I excepted, but maybe that's because I now know that it can make a big diference what kind of Build I used (skills and stats) .
For me a warrior build I find difficult, but a ranger and mage is good for me. Now playing almost as a Priest and that's the build that's suits my playstyle best

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I was level 34 when I finished the Ego Draconis part and go to the FoV part (without making use of Wisdom, don't invest in the Mindreading skill and choose not the XP after solving a quest.
On this way the game difficulty remains good for me.
Some people here do also this:
make a "handicap" for themself like not investing statpoints after a certain level, or let uninvested skillpoints "uninvested" ...
I myself didn't fidn so many Epic gear, but indeed the Epic gear is very nice

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About the Armour Sets :
Do not forget that wearing more than 1 part of a Armour Set give already a BONUS on each part of that set and the more items you're wearing, the higher the bonus will be on each part of that Armour Set !!
And like the Archmage Armour Set (I like it most of all sets, so far - playing now FoV part) : the Belt of that set is really special and come in handy if you frequently use skills with a high Mana cost (like Thousand Strikes, for example) !
Play and have Fun with the Dragon Knight Saga for a long time,
Find out what suits you best and you will say:
"That build is mine !"