Michaels was involved in :
1) First ever WWE Ladder match
2) First ever Hell in a Cell match
3) Most infamous moment in wrestling history (Montreal Screwjob)
4) DX (Without Montreal Screwjob and DX, there would be no Attitude era)
5) Involved in the first ever Elimination Chamber
6) Retired Ric Flair
7) Undertaker's streak became relevant after wrestling Shawn Michaels at Wrestlemania 25.
Michaels accomplished way more than Undertaker who is only relevant because of a predetermined overhyped streak. Undertaker is very overrated. Without the streak, his career is not that memorable.
HBK > Taker.
This is one of those debates that will stand the test of time,lMO.
Because of the type of performer HBK was, he connected with a bigger demographic of the WWE fans and is generally favoured more in any debate with Taker. Actually, there was a list by the WWE naming the Greatest Superstars in the WWE ever, and HBK was #1, whilst Taker was #2.
That being said, I'll reply to your reasons for HBK being better, by saying why Taker is better.
1) The Undertaker character basically created the Hell in a Cell,Casket and Buried Alive matches amongst others.
2) See Number 1. Undertaker was the other half alongwith Shawn Michaels.
3) the Undertaker reportedly made Vince Mcmahon apologise to Bret Hart for said incident. Was a major galvanising effect in the locker room after that incident occured. Shawn Michaels wasn't the hero in it either, don't see why it should be boasted about,tbh.
4) Another report stated that Undertaker threatened Shawn Michaels to do the job for Austin at WM14 due to HBK apparently not wanting to. Him not jobbing at the time, would have hurt the WWE's plans at that point as Austin was incredibly over at the time and HBK was injured.
5) See number 1.
6) Retired Shawn Michaels.
7) Actually, Randy Orton made the WM Streak known to the WWE audience, and from then it became a staple attraction on the WM card yearly.
Cheers.
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