Dark Souls boring, or too difficult. That's a laugh and a half. Although how can a game be boring by It's graphics? That's an odd one, considering the fact that they have mods, and some are texture mods which do improve several aspects.

Then again if you've played Demon's Souls I suppose Dark isn't too difficult. Bloodborne is the drastic change we Souls fan are going to adapt to, considering the fact that It's a much faster paced game.

Witcher 2 can be difficult, then again that would be your own fault for not preparing Geralt for fights, which plays a major role in the game. Then again I've had my fair share of... Frustrations, mostly my fault, however.

Pillars of Eternity should be on your list for RPG's to buy in the coming months, and go ahead and buy Inquisition. Great game, lot of fun, and good use of FROSTBITE 3. Not exactly challenging, though it can be since the game does have regions with higher level enemies, which don't scale to your party.

Icewind Dale EE is also a good recommendation. Very challenging game, and despite it being quite old, holds up well for the things it does great in. Fallout 2 or Fallout: Tactics if you feel like going back to a time where RPG's were in their golden prime. Fantastic games, challenging, lots of fun.