This.
We're already gonna have big gray area questions if the track is just over 400 (say 410) feet above grade and only part of the train actually makes it over the 400ft line. If no part of the train crosses 400ft, that's just plainly not a strata though and I'll die on that hill.
Somewhat reasonable minds can disagree on whether or not the drop needs to be 400ft in total elevation change experienced to count (my position is that drop is obviously how we should classify coasters, but Cedar Fair has already staked their position on the other side of this argument with the records they've historically claimed at Cedar Point), but if riders don't make it to 400ft above grade and Six Flags tries to market it as a strata, I'll be first in line to give 'em hell.
Ideally, would it be taller than Dragster to take the generic North American height and speed records? Certainly. Do I think post-Cedar Fair merger Six Flags is likely to give Dragster's North American records away? Probably not. Classic Cedar Fair Ohio supremacy behavior. Ride experience-wise, the difference between 410 and 430 is almost surely negotiable so I'm not gonna be bothered if Phantom Spire is a little under Top Thrill vs a little over. Happy with the only strata spinner in the world for sure.
That said, if it's not a strata, I will be very disappointed. Not because the ride experience is likely to feel much different between 390 and 410, but because blowing up one of the only stratas ever built and replacing it with something that isn't in that same height class will feel wrong to me—and if they're anywhere near 400 anyway and they don't opt to spent the couple million that may be required more to cross that line, it will be a definite miss in my book.