The mystery over the assassination is now a big deal i think.
MC already pushing the original time to make its own path, but the correction are still there.
I think the problem with MC is that, he had no "Detective" capabilities to knows who's who behind an important event in his timeline.
If he'd known that, another interesting twist and plots are awaiting to him, because he's got lot to know whats going on around while he was busy training and be happy in his original timeline...
This is only my guess and conjectures....