Only two things really matter with the shoe:
1) What is the energy return of the foam
2) What is the vertical displacement of the foam under load
On's shoe will not be the same gamechanger that the Vaporfly was because both 1 and 2 face hard caps. The OG vaporfly already had 87% energy return compared to 65% for the Nike Streak, and obviously that number cannot exceed 100%. Precision steel springs top out at 98% or so; it's hard to believe that other brands haven't already improved on the original vaporfly foam from nearly a decade ago
When it comes to deformation, the WA cap on stack height puts some practical limits on how much the shoe can deform - you absolutely do not want to bottom out the foam, and you only have so much vertical space to work with. So again, vastly diminished returns compared to older racing flats. The Streak 6 had only 16 mm of foam in the forefoot (6 mm deformation); the OG Vaporfly 4% had 21mm and deformed 12 mm. You ain't doubling that again and staying under the WA stack height limit.
Lighter weight is nice, but as of two years ago the Alphafly was both the heaviest and most performant super shoe on the market. Foam and deformation can easily beat out a lighter shoe.