I think there can be a successful Oath deck out there right now, but it needs a lot of focus and testing to generate the optimal configuration of creature package, counter package, draw suite, removal suite, planeswalkers, Dredge plan, PO plan, Null Rod choices (run it, ignore it, fight it), TV/Key choice, Karakas plan, and managing the triumvirate of intrinsic self-inflicted wounds: automilling, useless cards in hand, and death by Spirit token.
Punishing Oath Emrakul/Griselbrand is formidable overall, and can run Null Rod/SS but is slightly soft to combo and soft to Karakas.
Saheeli Oath transfers the issue of useless draws away from the creatures but then moves that onto a combo piece that is generally horrible by Vintage standards. We call her the "blue Bridge from Below."
Gush Oath was smooth and consistent but now Gush is restricted.
Auriok Oath is likely good right now with the right supplements but can't be tested on MTGO where many of us get some portion of our testing experience.
Landstill/Oath decks seem as fine as ever, attacking on two distinct axes. Still, it has the "Treetop Village, go" thing going on.
Evil Oath decks might offer a lot. By Evil Oath, I refer to prison-esque strategies that can use Sun Titan, Trinisphere, Rod, and land destruction to help combat a natural predator which is combo. I've started looking into a preliminary build but am not sure whether it will be ready in time for something like the NYSE.
Overall, it takes a long time to get Oath "right" and there is a lot of analysis and balancing that must occur. The end result can pay off spectacularly but a lot of the format's mental energy is being poured into neo-Mentor, Big Blue, Paradox, Shops/Eldrazi, and Dredge atm.