I got my hunter up to level 8, this is how i feel the conversation must've gone when this game was conceived.
Activision: So, Bungie, we want you to make an MMOFPS.
Bungie : A what?
A: Like an MMORPG but a first person shooter. Wow's numbers are gradually declining.
B: Ok, so like WoW with rifles?
A: Sure.
B: Can we make a whole race of Cortana looking people?
A: Sure, why not...
B: What about the Prawn from District 9?
A: Umm... I don't think we can get away with that... maybe make them robots bet retain the basic facial features?
B: Yeah.. we can do that... OH YOU KNOW WHAT? I loved the little scanner ball from Conduit! We've got to incorporate that too.
A: Are you gonna change it's functionality?
B: No, but we'll use Peter Dinklage instead of Kevin Sorbo for the voice though...
A: Hmm, ok...
B: We'll HAVE to have Landspeeders..
A: ok...
B: And the basic ships will be A Wings.
A: Ok...
B: AND we can make to Traveler a giant anti Deathstar.... You know, like a lifestar! It fixes planets instead of destroying them!
A: Umm... lets not add TOO many more Starwars references, they are owned by Disney now...
B: Good point... how about we add the throwing knives from BLOPS?
A: Yeah, that's one of ours, go ahead.