@Morden Man I think, personally (as the resident OOC spammer), that game wide events should be a thing but built upto. Usually within one of the key groups (in this case, the Justice League), an Arc that can be interupted with Solo arcs and then builds to a climax which lets more people throughout the RP get involved before the resolution and then things calm down again.
More for the fact that it adds some spice, than direction. I don't know about everyone else but I am happy to run solo arcs and occasionally have some interaction but I think with the authority of GM (or Co-GM... -eyes
@Lord Wraith-) it creates a story that other people can get involved in, with ane element of suspense and surprise. As they don't know what's going to happen!
That's just my two cents anyway.
Also as Natty, Morden and people who know me know I like to plan out future arcs so if someone is struggling I can help out if you want.