Most top end Raekor players completely skip Electrified mobs in Greater Rifts.
You also skip fire chain packs as well in higher GRs. It will typically fuck you up faster than electrified a lot of the time. Pretty much just something you have to come to terms with playing raekor is that eventually you will be skipping mobs, but, really that isn't much different than how leapquake skips pretty much any pack of white mobs where there is only 1 or 2 guys total. Just not worth it to stop and leap, you're better off using those leaps to just go through the rift faster.
As for playing raekor itself it is pretty hard to get a handle on at first, but, it's not that bad. There are some enemies who can't be moved by the charge, but, these are the same enemies that are immune to displacement effects from stuff like Pirhanado and Black Hole as well. Something to keep in mind with raekor is that there is no real reason to actually drag mobs places unless you are going to pick up some more guys. Raekor does the most damage when you are spamming charge in a tiny radius because you aren't bound by the cooldown so the less distance you travel the better. The only time it's worth it to move enemies is when there are a lot more guys you could pick up (leading to more damage from vile ward).
Anyway, for Immortal Kings, no need to really go after that set first. It is a support set meant to be combined with builds when you have spare slots. There is no such thing as an "IK" build really, you can use IK with just 4 pieces of gear (4 piece IK or 3 piece and rorg) which leaves
a lot of unused slots of equipment. Currently there just isn't any game changing legendaries that you can put there to make IK specifically better. The only thing is T&T, but, T&T + IK alone is not going to get you very far past T6.