If we're lucky, the assassin plot will lie in the background for an episode or two. We'll get a few reminders to build up tension (a quick cut of him in transit, seeing him in the background for a moment, that sort of thing), without doing anything overt. Then we'll get whatever crisis he instigates, our heroes will overcome it, and we'll proceed to the endgame. (Obviously I'm assuming our devs won't pulling an Acting Lessons and kill off one of the main characters for the sake of drama.)
If we're unlucky Prizer will claim the evidence against them can't be corroborated now that the wife is dead and thus the injunction against Polygene will be enforced. The injunction was already a serious stretch, but this would make Lisa and George look incompetent; you don't get to run a multi-billion dollar pharmaceutical company without knowing how to play politics and throw your weight around, yet somehow they're entirely reliant on Mallory's budget-stretch employer for their defense. The less we rely on that plot point the better.
I'm not overly fond of the Bond-villain antics interrupting the story, but they seem like the lesser evil here (as long as the assassin's crisis doesn't last too long).
On the contrary, he's precisely the sort who needs it. Redemption serves no purpose for people who never sinned in the first place.
I just hope Christian's "redemption" comes from genuinely regretting his actions and seeking to make amends rather than giving him a really sad backstory and hoping we'll forget about what actually happened. Being redeemed doesn't magically make everything alright, it means acknowledging that real harm was done and needs to be addressed.