Nope. I play on normal first play of all games, no problems with difficulty at all. Its not challenging. Some games I'll play higher, just 'cause I felt like it, but I won't back down from that harder difficulty as there isn't any point to it. Rather than swapping down and having the game be a cakewalk, I'll just learn to play the game. Most of the time that's the only reason a harder difficulty is hard - 'cause on Normal or Easy you don't have to know how to play the game, and once you learn how to it becomes easy.
There are some few exceptions to this, namely ones with utter BS AI on the higher difficulty levels that honestly just cheat, and I'll know about them beforehand and not bother because f*** that.
As an example, Witcher 2, your example. The boss at the end of the first chapter [Not the intro, once you're at that town or W/E and you get into a fight with the Kingslayer]. I got my ass handed to me by him. Every. Fucking. Time.
There were also problems with large numbers of Nekkers and such, but constantly rolling back then forward allowed me to survive them easy enough.
After losing a good 10 times and making no progress, I went online to find out how to beat him. That taught me the game's basically instant-win strategy of using Aard [Or whatever the one that knocks them back and minorly stuns them is] then wailing on them with 2-3 heavy hits. Works on any enemy. Level it and Aard becomes a wave that knocks back many enemies. The game just became trollingly easy after that.
Also, once you get one of those +50 health upgrades... Its a lot easier. It feels like your health has tripled. Get two and you are god.