I don't know if it was the taser so much as it was the who followed by what went down the Nitro after.
It was beyond shocking when Goldberg lost the title. He hadn't lost steam yet and there really was no need to take the title off him. Granted this was Nash's first WCW title, but it was freaking Nash. He didn't need the title, certainly not at that point. WCW was failing to build its own stars, and they went with giving a then 40 year old Nash his first title.
The finger poke of doom the following night just made things worse. At least had they kept the title on Nash and made the Wolfpack heels it would have had some semblance of freshness. The fact that it was Hogan at the head of the nWo elite made it automatically stale. And let's face it, the elite came out to the Wolfpack theme, they were the Wolfpack lead by Hogan.
Then they chose to embarrass Goldberg pretty hard afterwards with the massive tasering and spray painting incident. If someone was actually tasered that many times in real life, they likely would have gone into cardiac arrest.
The stun gun incident was so reviled because Goldberg never managed to recover it. The remainder of the career of WCW's hottest star of the late 90s was marked by a series of diminishing returns.
All men fall to a stun gun. They might as well have used a real gun and made Goldberg lay down. It just kind of breaks the basic promise of the premise of wrestling. Dudes or chicks fight, toughest one wins.
One of the problems with undefeated streaks and invincible athletes is that you write yourself into a corner. Look at what WWE is doing with Lesnar today. How are we supposed to believe that someone can hurt him if he just bloodies and destroys everyone.
Here's how I would have booked the end of Goldberg's streak. I wouldn't have taken the title off of him in early 99, and not the way that they did. It never should have been Nash or anyone in the core nWo. They needed to bring in a new star, and someone that wasn't over 40.
Hall, Nash and Hogan were all over 40 years old at the time of the tasering/finger poke of doom. They should have waited the year and built up someone new to beat Goldberg. I'm not sure who that should have been, but not Nash.
Booker T was about to become one of their top stars, as was Scott Steiner. There really wasn't a very viable option and sooner than later they would have had to either build an "anti-Goldberg" or do something like the taser.
The anti-Goldberg would have been a heel who goes on a cheating streak to become undefeated. It could have been an existing guy, or someone young. Palumbo, O'Haire, Jindrak and Stasiak were all coming up through their system.
The taser would be remembered better if it wasn't followed by the finger poke of doom and the total molestation of Goldberg that followed it. Had Nash had a real run with the title and the two nWo factions pulled the double turn, then it would be remembered better.