Quick bit of sucking up to start: Love the recent WCW stuff! On that note…
I know the answer to all this is, “because WCW,” but it seems to me the booking for Sting's title reign is so simple. Wins the title from Flair at the Bash. Wins to rematch at the Clash of Champions, (in a cage maybe,) to end the feud. Beats Sid at HH. After
the match Luger turns on Sting, and there's your Starrcade main event with the Clash Black Scorpion magic trick show now being the contract signing. I mean, how hard is that?
Also given the reaction the Skycrapers got at Starrcade and seeing as how Sid is lousy in long matches anyway, why not team them up full time again and let them have hoss matches with the Steiners?
Sid actually suffered a punctured lung in a match with the Steiners so he might not have been too keen on that idea.
Sting's reign went like it did because Jim Herd ABSOLUTELY had to move Flair out of the main event IMMEDIATELY in his own mind. Sting had to win and then, bam, Flair was instantly a tag team wrestler in the midcard and the fans would just accept it because he said so. But yeah, 100% they could have gotten at one more show out of the Flair challenge to settle that for good, and Sting could have continued going through the Horsemen as needed until it was time for Luger to turn on him.