Quite the opposite, I think Dark Reign has marked the elevation of Norman Osborn into Marvel's villainous A-list. Even as the arch nemesis of Marvel's flagship hero, the Green Goblin was something of a non-entity in the wider Marvel Universe. Not the case anymore.
I don't see Osborn being killed off at the end of Siege, but I do think him becoming Green Goblin once more is likely. Which is kinda a shame, really, because I almost think he's a better villain as Osborn than he is as the Goblin. That said, Ellis did a good job writing him as Green Goblin at the end of his Thunderbolts run.