I was thinking about watching it but thanks to you, I'm not so sure anymore lol. Well, if I'm in the mood to explore a new universe, I'll check this out. At least it seems worthy enough for that purpose.
As long as the profits stay strong, there is certainly every incentive to keep the MCU going, but I believe they will need to depart from comics to keep the storylines fresh. Many of the concepts that work in graphic form or for comic fans will not necessarily be interesting for moviegoers. Secret Wars is a great storyline, but I have no idea how it could be shot with any kind of credibility.
The twist is the essence of the movie. Like you, I've never a prolonged revenge thriller. Usually movies do a mother of all fights at the climax to end the movie but "I Saw The Devil" was different and I admire it for that. The brutality makes it even more beautiful. I just finished watching "A Hard Day" on Netflix and the violence in that movie pushed the boundaries even further.
Daniel Radcliffe is kinda unlucky in that he will forever be seen as harry potter by our generation. Unless he delivers an epic performance in another role that blows people's minds, it'll be hard for him to get out of the "boy who lived" shadow.