It is unknown where in the tier list she's going to be.
She certainly is a good character this time around, that's for sure. But the tier list will reflect which characters are being played and winning in tournaments.
We don't know where certain characters are going to be in a few years either, Melee changed a lot and the tier list reflected that as players got better and ATs were found.
Also, keep in mind that Zelda has gotten a little more popular, but not wildly popular despite her buffs. Many of the people on this board are the same ones who were lurking on the Zelda Melee boards.
If Zelda's aren't winning tournaments and the back room doesn't have Zelda advocates who legitimately feel she's worthy of being high tiered, I wouldn't be surprised if she only places moderately well (that might be where she deserves to be ultimately).
Time will tell. If anything, most of the people on this board are fans of the character herself, not the tier placement. The fact that she's much better this time around is icing on the cake.
As with Melee's tier list, ultimately the top half of the list will be pretty accurate and the bottom half will probably always be debated (since the bottom half will have few tournament players to really measure them accordingly - this isn't the fault of anyone, simply its harder to judge exact placements of characters who get less tournament play).
My guess is that Zelda is good enough where despite popularity she'll be high enough in tiers that her spot won't be super debated, it'll make sense given the matchups. As opposed to Melee, where despite an agreed tier list, there was still debate amongst dedicated players over Zelda/Bowser/M2/Pichu's placement amonst the worst 4. Not that it mattered much.