The Witcher 3's storyline is too long according to devs

[Syntax]

I probably have yet to finish this game due to me just playing others, and always seemingly coming back and forgetting a bunch of the controls/gameplay style. I don't think that it's boring or that the story is too long (when we compare other games like Skyrim that seemingly have no ending), but I think that it does take someone in a specific mindset to want to play it for hours on end. 

[Reality vs Adventure]

I just finished the main story and since I enjoyed it, I have to say it wasn't too long. It was a beautiful journey and highly recommend it to others who really need to give it another try. One of the best games. I still have the DLC to play and a bunch of quests. 

[Hammerklavier]

I did finish the story to Witcher 3, but my impression was that it could have been trimmed in half and still felt appropriately epic.  There were so many points at which it seemed to drag and lose momentum, so many nested quests along the lines of "find character A, but first you must find character B because they might have intel on where A is, but character B is missing and requires you to find character C".  Almost as though the developers were determined to pad their main story as much as possible.

For some players, I'm sure the length felt absolutely fine, but I do tend to be somewhat more on the impatient side when it comes to the pacing of video games.  Overly lengthy main campaigns is one of my personal pet peeves that causes me to abandon a lot of highly acclaimed games before finishing them (both Half-Life games, System Shock 2 and Alien Isolation being a few examples).  Sometimes less is more, and a shorter campaign can prevent the gameplay from becoming stale and repetitive.