Seems like a good thing, to me, making assassinations harder. Now I won't speak to people in DM plots who have one life, but for everyone else...
It doesn't make too much sense that you can just kill them, throw their corpse over your shoulder and vanish before anyone can react. If anything, that sort of thing mostly seemed to cause conflict and hard feelings, and a certain lack-of-fun. Actions having consequences is all well and good, but with this change it seems you might have to actually set things up more carefully than smash, grab, run. Heck, you might even have to make it fun and interesting for the person being ganked, which I think is worth striving for.