Looting is different from Brainstorming and doing it at instant speed is a very real difference to the game - consider Snapcaster Mage.
Agreed, looting is different from brainstorming; usually looting is inferior, unless you have some graveyard tricks, because you (often) see fewer cards and don't get card advantage. I think the lack of card advantage is the most important difference, one which is crucial for blue decks.
Phasing a creature out at instant speed allows for interesting combat tricks
Usually not relevant in a vintage blue deck, unless things have changed drastically since I last played.
While JTMS has a game winning ultimate, I have fought against it and won a few times. Taking 3 turns back to back will usually end a game of Vintage.
It sounds like you're presenting an exceptional case (wining versus the Jace ultimate) as a reason against it. The Jace ultimate will usually end a game of Vintage, too. Taking 2 extra turns requires other stuff to win with it. Admittedly, you probably will win if you get to this point, so the difference in value here isn't as great as the other points.
I think I like Teferi over JTMS in the current Vintage meta but that may just be my opinion.
By all means test it out and let us know!
I don't want to rain on anyone's parade, but JTMS seems superior in almost every way.
Brainstorm each turn > Loot twice each turn
Bounce a creature > Phase out a creature
Game-winning ultimate > Take 2 turns
Yes, there are some subtleties that I'm ignoring here, but the new Teferi is pretty much strictly worse.
I haven't liked BSC for a long time now, though I don't get much of a chance to play Vintage nowadays, so what do I know. The thing is, he's vulnerable to Dack Fayden, JTMS, and now Oko, three big planeswalkers that other blue decks could reasonably be playing. Not to mention STP.
I've always had good success eschewing Tinker entirely; my playstyle tends more towards hard control. Conversely, I can remember several times my opponent had Vault or Key in play, which I was able to ignore entirely because it did absolutely nothing on its own. But maybe this is just me.
Anyways, a suggestion you could try.
Everything that facilitates the things I don't like, and inhibits the things I do, is unfun, broken and format-warping.
Conversely, everything which facilitates the things I do like, and inhibits the things I don't, is fair, fun, interesting, and helps maintain Vintage MtG as a vibrant and strategically deep format.
Maybe a pet peeve of mine, but I've never been a fan of Vault-Key. Every time you draw one of the components of the combo, make a note as to whether you'd rather have something else. I've played against Vault Key many times and only lost to the combo once IIRC; can't remember how many times I've smiled inwardly when my opponent dropped Key or Vault, but didn't have the other piece, and gave me virtual card advantage. Synergy is great, but these cards do almost nothing of value on their own.
I'm also not huge on Top, as it requires you to constantly sink mana into it and generates no card advantage by itself.
These thoughts are probably at least somewhat heretical; as always, think through what makes sense for you and test things out.
Edit : Just scanned through your list again. Hurkyl's seems a bit suboptimal; you'll buy yourself one turn vs. Workshop, and then what? You aren't a combo deck, so your opportunities at that point seem underwhelming. Maybe a By Force or Shattering Spree (tho probably not enough red for that one).
So whats the reason for the one crop rotation? Just one seems weird.
Yeah, since you're not running Null Rod main, Expedition Map seems like the better choice.
I love 5c Stax and would love to see it come back, but running so many Karn, TGC seems iffy with that mana base. Running a few Maps to search for Academy would definitely help.