What!? how does Dalaran showing up to bombard Orgrimmar from a long distance has to do with players "feeling that Dalaran defeated Garrosh?" so judging by this logic no lore character has to appear in SoO because players will feel like it was Varian,Vol'jin or Lorthemar who killed Garrosh (lorewise they do anyway.) and there should be no siege weaponry or NPC armies sorrounding Orgrimar because players should feel like they are defeating Garrosh by themselves and they don't do it because Orgimmar is f**** besieged by nearly every powerful faction within Horde/Alliance.Moving Dalaran to use in the Siege of Orgrimmar was considered, but it would have caused serious performance issues for many players. It also may have reduced the impact that players had as far as feeling like heroes. Players should feel like they were the ones to defeat Garrosh, not that Dalaran showed up and they did the job.
Performance issue? how does a mini version of Dalaran (a low model or a bitmap.) hinder a computer's performance? just say "it makes Alliance feel awesome and that's no a priority."
and lorewise Jaina is pretty much driven to see Garrosh fall. why on earth would she hold back when both sides need their best weapons to take Garrosh down???