The Marvel comics character Deadpool, in 616 and most other incarnations, is a normal human given an offer that he couldn't resist when he developed cancer. The offer involved being experimented on and given a distilled copy of the X-Men character Wolverine's mutant healing factor. This is constantly referred to, and links Deadpool to Wolverine in a very intimate way. Mutants typically develop their powers during adolescence/puberty due to stress and hormones, the powers sometimes in response to environmental conditions or genetic history.
X-Men Origins: Wolverine has a DINO version of Deadpool (in Name Only), that not only inherits Wolverine's mutant healing factor, but a few others as well. Then X-Men Days of Future Past happens and wipes out this timeline.
The 2016 film, set in the new timeline, changes this by making Deadpool a latent mutant, who's powers only develop through repeated stress trials, and in response to environmental conditions (cancer, death). His specific connection to Wolverine was removed, as was the overall connection to the shared backstory of the Weapon X program.
As Wolverine and Deadpool exist in the same movie universe, with no complications like the other comic movie universe, why was this drastic change to the character's origin done?