Taker made far more people than he squashed.
Yokozuna, Mankind, Kane, Cena, Big Show, Brock, Batista, Edge, Orton...
All of them had their first major storyline as main eventers or the one to make them main eventers with Taker. He was the one that the next young star learned from and got a push from.
Established stars also had feuds with Taker and came out strong or even on top...Austin, HBK, HHH
Valid points, out of those I'd really give you Edge, probably Brock and Batista.
Yoko I don't think was ever really made, he was designed as the monster who was fed to however was needed to go over, it was the Hulk Hogan King Kong Bundy playbook played over and over again.
With Mankind, I would argue that it was mankind and his crash test style more then anything that Taker ever did.
Kane didn't really come out of his fued with Taker being more over, I would argue that his tag team alliance with X-Pac more then anything else.
Cena, sure, but Cena was already starting to see his immense ruthless aggression push.
Big Show sure, absolutely.
Brock, absolutely his win over Taker at Wrestlemania was huge for his career, but that took sacrificing the streak, and in hind sight it might have been a wasted thing as Brock was already at the top of the card.
Batista yeah I can see it.
Edge - I would argue that the transition from weird Gothic guy to the whole Lita love triangle to the Rated R superstar character more then any one feud or match that launched him into the stratosphere.
Orton - Sure but really did it give him that much of a bump?
With the established ones that you mention, I don't know if he really had a big effect on HHH, HBK or Austin, I would argue that he was the King Kong Bundy of those feuds, but his rub meant very little to their career trajectories.
The one that you forgot though was that Taker was invaluable to the HBK Bret feud when Bret was a heel, with the spit heard around the world, and the Bret Taker mini feud.