Ruin the character? If you have read the Conan books by Robert E Howard you would know the Arnold Schwarzenegger version is the ruined version of Conan.
every time anyhting in print gets made into a movie there's always some hardcore fanboys bitching about how the movie "isn't being faithfull to the source material"
there are some movies that i personnally consider to be "better than the source material"
Daredevil
Ghost Rider
Blade trillogy
and especially Watchmen
in the Daredevil movie there was no spandex, bullseye wore street clothes, the main villian was Kingpin instead of Stilt-Man, Purple Man, the Owl, or any of those other villians from the Daredevil comic that would have looked stupid on the big screen, the Kingpin was played by a profesional actor instead of a profesional wrestler as one would have expected, and the whole second half was crammed full of moments where it looked like a sequel was inevitable, aside from the CGI sequence that was unmistakeably a frame-for-frame copy of a scene from the Matrix, Daredevil was an awesome movie
Nick Cage's face was clearly too old-looking for Johnny Blaze, and the movie would have clearly worked alot better with that guy that played "young Johnny Blaze" just going ahead and playing Johnny Blaze thoughout the entire movie, but other than that the movie was flawless, the origin story part was so completely different than the comic that everyone bitched about it, but for me, the movies version really was better than the comic, cuz it made more sense
the trillogy of Blade Movies looks not merely better than the Blade comics, but also clearly better than any other movie trillogy that Marvel has done so far, but i'm still kinda hoping this new spiderman trillogy will be spectacularly awesome, or at the very least be a little better than the first one
i loved the Watchmen movie so much
because of all the differences, not despite them, to me every moment where the movie differs from the graphic novel looks like Alan Moore made a ton of mistakes and Zack Snyder fixed them, especially Doctor Manhattan's dialogue, editing out the unneccassarry caracters and changing the giant squid into several bombs