I really, really dislike rolling INT off for sockets on jewelry. You generally don't gain that much more damage, and in turn you lose the mitigation from all resist that INT gives you.
I'm not saying it's an absolute rule, but I would have to really have a good justification for myself to roll off INT to socket, as opposed to another damage stat.
edit:
for firebirds, a good sun keeper+source beats out a good maximus pretty handily. But a good maximus is easier to get, and beats out a mediocre sun keeper. One thing to keep in mind when evaluating weapons for greater rift use is the way you play in greater rifts, which is generally herding white mobs into elite packs and trying to always be fighting elite packs. That's why furnace is crazy, in addition to the biggest firebird DoT you also can generally play rifts in such a way that you get full benefit on a 2H from the 40-50% elite damage bonus.