First things first. THIS is the 'classic' steel cage. Not this
I couldn't find images, but you can even go back further and see wood framed steel cages with actual chicken wire meshing, and not the chain link fencing that eventually became the norm.
Sorry, but reading this thread, it's really been bugging me seeing big blue referred to as the 'classic' cage, as if this was how cage matches always looked until they came up with the recent idea of using chain link fencing.
Also I see where someone mentioned how old cage matches never had this 'new' escape through the door rule? For the longest time in the WWF, escaping the cage was the ONLY way to win a cage match. There was no such thing as pinfalls or submissions in WWF cage matches. That was the opposite everywhere else however, as the only way to win a cage match was through pinfall or submission.
Anyways, the WWF designed Big Blue for Wrestlemania 2 for two reasons. It was easier to show the action inside the cage... and there was less chance of accidental blood.
They did away with it later for another couple of reasons. They wanted bloodier cage matches, and the blue cage was causing more injuries. Now they don't want the blood again, but they're also concerned about hurting the talent. Plus the current design they use is perfect for TV or PPV, because there's no down time in setting it up. They simply set it up before the show begins, and then take a minute to lower it however they see fit (whether on commercial/promo break, or if they want to make a spectacle of it).
You won't see big blue back, unless they can figure out a way to make getting thrown into steel bars safer for the workers.