We're no different than Paul; where much is given, much is required. High revelation just means you get to play on hard mode. If God wants you to be really smart, then he will help you get really smart; but also give you an opponent that is smarter than you to keep you humble... and if it takes a messenger of Satan tormenting you to keep you humble, then that's what you get. And we really can't even complain that it's not fair; because Jesus was already most-humble and had Satan-himself messing with him right off the bat.
how would you spot someone who isn't in check with his otherwise vast knowledge?
I'm not sure if it's necessary for us to spot, or otherwise do anything about that sort of thing- that's between them and the Lord and I totally trust that he will deal with that, one way, or another. And somebody like Paul, some of the things he wrote, you read it, and you're like
"Wow, he really could have said that in a nicer way" but also, nobody can doubt that he loved the Church and would serve the Lord at any cost.