It's in the past, I say let it stay there. It wouldn't make sense for Barrett or Otunga or "Ryberg" to go back to being Nexus, and it wouldn't really work doing it with a new set of NXT guys since it would no longer be a fresh idea.
They really could have done it better the first time around, of course. Nexus losing their first big match to prove themselves? By elimination at that? (Meaning they each had to take a loss, whereas a normal tag team match would require only one member to take a loss.) Imagine if the Alliance had lost at Invasion 2001. Wouldn't exactly make them much of a threat over the next four months, would it? Imagine if Giant pinned Hogan at Hog Wild 1996, right as the NWO angle was taking off.