Like most, I think Levy is in the lead at present. But I genuinely wouldn't be surprised if Marla Mindelle pulled it off for Titanique. I think she's the singular reason the show worked as well as it did. She's a force in the show. It will just come down to whether folks this she and/or the show are just too unserious.
With the Mazzie/Levy comparisons, I think it's tough that Mazzie was extraordinary in the original but didn't win the Tony. If one thinks that Levy is great but slightly less transcendent than Mazzie was, does that impact voters? And there's also that voice in the back of my head saying Levy was even better in Next to Normal. While that didn't make it here, the proshot did, so will anyone hesitate just because they feel she was better elsewhere? For me, none of that detracts from the excellence of her work or how much she deserves a Tony for it. But they're factors that I can imagine getting into people's heads. I could also, certainly, be overthinking this all.