Alright, bypassing my usual superfluously worded posts, here's a quick thinker for ya.
Destiny will use each planet in an Easter-egg-ish way to represent each of their past game series'. For instance Mars will be Pathways wherein you will go into deep caverns and ruins to find new enemies and ancient evil. Venus could be Marathon, exposed to a heavily colorful intriguing new setting while having to deal with a rouge AI. Or 3. And the examples roll on.
It's just a crazy idea I thought of just now and was curious as to who else would think it's plausible. Obviously it wouldn't be a central element to the game but it would be a nice hidden homage to the aged fans.
It's a long shot but hey, at this point, what isn't?
I wouldn't be surprised if there were nods to previous games in multiple environments as you suggest, but having each planet represent a game would suck. We would have seen everything before, and it would be too history-centric (there must be an actual word for that, anyone?)