I heard somewhere that the plan was actually for Bret Hart and Stone Cold to have a rematch from their Wrestlemania 13 match, with Bret putting Austin over to kickstart the Attitude Era, I imagine in the same vein that Shawn did.
I'm thinking I might've read this in Dave Meltzer's account of the Montreal Screwjob that he put out way back in 1997 shortly, after it happened. The report contains many booking scenarios that were discussed by WWE and Bret Hart throughout that year, and I believe one of them was the idea of Bret being the one to put Austin over at Wrestlemania XIV, which obviously Bret had no problem with.
Whether it was Bret Hart, Shawn Michaels, Undertaker, or the Brooklyn Brawler, somebody was gonna go in as champion and put Stone Cold over, that much is obvious.
Obviously Taker and Kane would've happened. If the top two matches are Taker/Kane and Bret/Stone Cold, the question is, where does that leave Shawn Michaels. It's possible that if the Casket Match at the Royal Rumble took place anyway (remember Taker's and HBK's feud had no title on the line at first, thus it's likely the feud could've continued whether HBK was champ or not), and thus Shawn experienced his back injury, he may have just retired right then and there and would'nt have been at Wrestlemania. In reality the only reason HBK had one last match was solely for putting Stone Cold over. If Bret is still in the company, then HBK wouldn't have been needed to put Stone Cold over. Even if Shawn had went over on Bret at Survivor Series and been champ and a match between him and Stone Cold was the plan (just like what actually happened), if HBK experiences the career ending back injury that he did, then they could easily change plans and have Bret fill in by getting the title back (maybe on Raw sometime after the Royal Rumble, or at the February ppv) and re-start their old feud with Stone Cold.
But if the HBK/Taker match at the Royal Rumble never happened, and thus Shawn didn't have to retire, and we're still getting Bret/Stone Cold and Taker/Kane, that does leave Shawn with an open spot. I saw someone mention that Shawn was planned to wrestle the Rock. But remember, by Wrestlemania XIV, the Rock was already a heel in the Nation. I suppose we could've had a heel vs. heel match, but I wouldn't that to be likely. Honestly, not to sound pessimistic or like an anti-HBK guy (cause I'm not at all), I could see Shawn having another fit and saying screw it and taking himself out of the equation for Wrestlemania (much like he supposedly did at Wrestlemania 13). If he's not gonna be in the main event against Stone Cold, Bret, or Taker, then "fuck it." I kind of think that scenario is more realistic. I don't see him taking a "step down" to face a mid-carder at Wrestlemania, be it the Rock, Owen Hart, or Ken Shamrock.
The only other possible scenario is that maybe they could've begun a power-play angle with D-X and have him face Triple H for control of D-X. Perhaps with Shawn not getting the title from Bret, and maybe losing to Taker at the Rumble (or barely beating him like what happened), Triple H could start to question HBK's leadership and come out and say he could be a better leader. This could lead to jealousy and tension, and finally a huge confrontation and a match for control of D-X is set up. Then maybe the New Age Outlaws could've interfered in the match, or X-Pac could've returned one night earlier, and cost HBK the match, thus forcing him out of D-X and starting the Triple H era of D-X? Which could've then turned HBK back into a babyface for awhile until he later joined the Corporation to get revenge on D-X.
Yeah, I think that's what I'll go with. Your main matches for Wrestlemania XIV:
Bret Hart vs. Stone Cold Steve Austin for the WWF title
Undertaker vs. Kane
HBK vs. Triple H (for control of D-X)
The Rock vs. Ken Shamrock
and maybe a match between Owen and Davey which would've added another classic match to this Wrestlemania, making it even better.