Maybe not Easter eggs per se. I don't want to be playing Destiny and be reminded of what 343i did to one of my favorite franchises. But. Subtle Dialog references would be nice. Having some story NPC's make little comments from the halo series. Nothing so extreme as quoting one of Chief, Arby, Cortana or Johnson's iconic speeches like Johnson's "Regret" joke or Chief's "I thought I'd try shooting my way out". But little things like "Knowing what the ladies like." Or having a female NPC tell you to "Wake up, chief."