Unfortunately both stuttering and frame skipping are very common in a lot of games these days even if you have a high end system. It doesn't go away if you put the games on lowest settings, and I've encountered some cases where the stuttering actually gets worse if you lower the settings. Some of my friends do not notice it, but I get really irritated. It just kills the mood and flow of the games for me.
I really hope DX12 helps with these issues in the future titles, but I remain very skeptical.
You do of course realize that no amount of game development wizardry can ever guarantee your game will run 100% smoothly on your particular PC, because there are countless variations and not all PC's are built well (no offence to you and yours, of course).
The responsibility lies with the PC gamer to ensure his PC is up to the task, unless it is an "Arkham Knight" situation.
Stuttering and frame skipping in Witcher 3 is very much caused by PC configuration issues, very often lacking in the CPU department. I have witnessed this first-hand when a friend of mine (as stubborn as he is) refused my advice to invest in a good CPU for his new PC build. Guess what happened? Stuttering galore!
I very recently built a new PC and invested in the best quality components I could possibly afford, including a i7 4790K CPU. Hand on my heart, I have not had one single problem running my game at 2.5K resolution on (more than) Ultra settings.
It is simply not reasonable to expect a cutting edge game to run well on an average PC build.
As for console gamers, they have a lot more reason to complain. But then again, CDPR performed a near miracle by getting the game to run on consoles at all.
When DX12 becomes the standard, we will definitely see a new chapter in PC gaming, that's for sure.