You can still get the Gjallarhorn if you don't preorder, just not the Iron one. Also, they had to completely redo the original story in the last year of development and didn't have enough time to make all new story missions, so they cobbled together what they had. Also, while I can see why you're upset about the Gjallarhorn Nerf, it's kinda obvious that they'd do it. If they didn't, the old raids and strikes would become a joke. Just imagine Atheon vs 6 Y3 Gjallarhorns with probably over twice the power of the Y1 one.