Part of what made the experience of Weapon XI in X-Men Origins: Wolverine so terrible was that, at first, everything looked so good. Ryan Reynolds as Wade Wilson is as good in his opening scenes as he was in the eventual Deadpool movie. However, at the end, not only is the guy we see not Deadpool, it's also not Ryan Reynolds. The Weapon XI version of the character was actually played by actor Scott Adkins, likely because his experience with martial arts made the fight scene easier for the filmmakers. The Huffington Post asked Adkins about the movie and, while the man took responsibility for his part, he blamed the studio for everything else.

I was part of the problem. I was part of the abomination of that character. ... I'd like to take this opportunity to tell you and all your readers that it wasn't my idea. I was doing what I was told by 20th Century Fox.

We don't think anybody was truly blaming Scott Adkins for what happened the last time around. He's an actor on a set and was barely more than a stuntman considering the limited focus of the character. The studio would never have listened to the him, even if he had numerous terrible suggestions for how to handle the part. At the end of the day, the studio is responsible for what ends up on the screen. They get to make those decisions and they get to take the credit when they work, but they also have to take the blame when they fail.