It would be cool if we could see the Blades of Crota out in the wild again. Yes, I know there's continuity issues, but gameplay-wise it would be fun to have the Blades again to make patrols more lively.
Edit: Let's hope DeeJ and the people at Bungie see this! =D
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I'd also be fun to have the wolves, hive, urzok, Kaliks, and the sword of crota brawling it out, it'd be total mayhem