Pump the breaks please. We need to walk this discussion way back. Firstly. OG Tezz does not "win you the game." It lets you search for and put into play Time Vault. It also lets you untap Time Vault. A lot of the time that is game winning, sometimes its not. But OG Tezz absolutely does not say "win the game" on the card, so we should stop evaluating the comparison as if it does.
Instead, lets look at this card for what it is. It is a 5 mana planeswalker with some pretty strong abilities. Certainly these abilities are at least strong enough to take a look at where it might fit in vintage. On it's face, I think we can limit this thing's potential to play in a big mana blue deck. It's casting cost is way to big to go in Xerox, and way to blue to go in much else. Oath? Mayyyybeeee. I'm lookin' at you Brian Kelly. But I personally doubt it. I mean, is it really better than, I can't believe I'm saying this, Arlin Kord? It for sure isn't better than Jace in Oath, since Jace can put back creatures on the top of your deck from your hand.
So within the big-blue shell, what does it do? It basically draws a ton of cards. It potentially draws more cards than Jace, which is saying something. But I personally don't think it is better than either of Jace, Dack, or Teferi. That last one being what I think might be the best comparison, and the card that squeezes this guy out of that deck. Essentially, the question is whether you win more in big blue by playing this guy over Teferi. That is what I doubt.
Teferi's "defend himself" ability is far stronger than making a thopter. And I'm not convinced that his draw ability is worse. Teferi always draws 1 card and always untaps 2 lands. This guy always draws 1 and sometimes draws a second card... To me that is a coin flip. If Teferi gets going, you win. If this Tezz gets going, you win. So I suppose the question turns on which one gets going more often. That has got to be Teferi… right? Because he essentially costs 3 and because he can remove permanents from the board, as opposed to making thopters.
I doubt it's better than Jace, because... come on. And I doubt he's better than Dack for the same reason. 3 mana vs 5 mana is a mile's difference.
So unless I'm missing something, this Tezz is limited to big blue style control, where he gets squished out by preexisting and superior walkers. I can't really reckon that one wouldn't just win more often by cutting this guy for an extra Dack, Jace, Teferi… or some utility card.