One niggle: you still won't admit that Jace was horrendous, will you?
Well, he said that Jace Standard was his favourite format of all time, so do you expect him to?
By the way, he's right about that. Post-ban Standard and current Standard are not nearly as interesting. There was one thing and one thing only wrong with Jace, and that was his price tag. You could conceivably play all sorts of different decks, including RUG Control (which was my personal favourite), Twin Combo, Boros, Quest-Vine, or RDW. With the notable exception of RDW, you'd definitely have played either a Jace deck or a Stoneforge deck if you cared about winning at all. But so what? In current Standard, you'd be foolish not to play either Snapcaster Mage or Primeval Titan , although also with the exception of RDW. There are always format defining cards. Deal with it.
Jace is simply a very powerful, yet quite fair card. Sure, he let you do some things that border on absurd, like Brainstorm putting back two lands, follwed by playing them through Oracle of Mul Daya . But lots of cards have interactions like that. How is it any more unfair than having a Shrine of Burning Rage at 10 counters on turn four? Or the engine of Life from the Loam + Raven's Crime in Modern? Or Wasteland + Crucible of Worlds in Legacy? At least the Jace + Oracle engine is fun for the player using it, unlike my other examples.
Jace also took a lot of thought and skill to play properly. Any card that emphasizes technical play skill is a good card to have around in my books. I absolutely hate losing to a less-skilled opponent due to unlcuky draws or insane topdecks from them. If my opponent is more skilled, at least I can say that they deserved the win, and learn from my mistakes, helping me become a better player. Losing when you made good decisions throughout the game and your opponent just has better luck than you is simply depressing. A consistently powerful deck that rewards you for making good choices is the kind of deck we should want to have in our formats. Better players should win more often.
The mistake with Jace wasn't in the card design; it was printing him in the second set while also doing a large third set. The very small amount of Worldwake packs opened in drafts caused the high price, which drove away players who couldn't afford it. If they had printed Jace in Zendikar instead, he would have been worth much less, probably no more than $50, and no one would have complained.