I also want to add this.
The seriousness of Rude's injury was questionable, to say the least.
For one, Rude had been suffering from back & neck problems for nearly 2 years at that point. There was talk of him leaving in '92, partly because of that and because of his pay being cut.
Now, the injury in Japan came on the heels of Rude's problems with WCW and a mere days after he vowed NOT to put over Flair, Vader or Hogan. The main event for the 7/17 PPV was to be a tag match, either Hogan & Sting vs. Flair & Rude or Hogan & Flair vs. Rude & Perfect and the end result in either match was for Rude to be pinned.
So, supposedly, Rude showed up to Philly, possibly to even wrestle but him & Flair had a rather serious argument, which resulted in Rude refusing to do whatever was planned for the night. That explains why Sting vs. Vader wasn't announced until the start of the PPV.
WCW booked themselves into a corner (although they got out pretty smoothly) by even giving Rude the title in the first place, knowing there was a bit of tension, based on him threatening to leave and refusing to drop the title to 3 of the 4 possible champions in the coming months.
Furthermore, the plan was to always hold off on Hogan vs. Flair until later in the year (possibly Starrcade).
That makes me feel that Rude would have retained the title against Vader and drop it to Hogan. Meanwhile, Flair would still do the heel turn, except on Hogan. If a possible BATB match was going to be Hogan & Flair vs. Rude & Perfect, that could have planted seeds for it. Maybe a possible War Games match with Sting, Flair, Hogan and somebody else, maybe Steamboat, taking on Rude, Vader, Perfect and somebody else, maybe Austin. And Flair turns on his team, walking out of the match. That could produce an angle based on jealousy, where you have Flair as the World Champion, feeling overshadowed by Hogan as the International Champion, leading to a unification match at Starrcade. And what's left is a continuation of Austin/Steamboat; since Rude wants to leave, he can; Sting can feud with Perfect and you still have Vader on standby for Hogan coming out of Starrcade.
Not sure if any of this was planned but based on original plans and rumors at the time, it all makes sense and Rude's "injury"/unhappiness with the company changed things but not necessarily for the worst.