Loki isnt bad lol, that much is absolutely clear by this flashback. And Im highly doubting Imu will stick around the entire arc.
Im saying that Elbaf should be Shamrock's arc, it was set up as much until he was called back. But he can just as easily be called back to Elbaf with the full GK team. We dont entirely know how this event is going to play out yet, nor what is even happening in Mariejoa, but there are clearly unfinished elements to Shamrock when it comes to Loki, not unlike Franky's grudge with Lucci in Water 7.