There hasn't been a major crossover since SI ended; that's a year, more or less (Dark Reign is a banner/status quo, not an event; to the extent that there's a central story to follow, I suppose it would be in Bendis' various books). And, depending on how big this is, it might not compare to that in size either. Quesada's talked a lot about moving to smaller, more localized crossovers.
Anyway, I'd say that the end of the DR status quo does need an event-type finale, since it affects everyone.
Be interested to see what role the heroes play in this.