So then there would be three forms of Mass?
Would it be done to eliminate both forms of Mass?
No way would this eliminate demand for the EF Mass. In fact, it would be taken as a slap in the face by traditional Catholics who have been hoping and praying for a restoration of the Traditional Latin Mass for decades. To be told 5 years after SP that they will now have to go to a Frankenstein Mass that sticks parts of one form with parts of the other would only cater to a very few in the Church.
If anything, a revision of the OF to allow traditional options would be the only real possibility: Prayers at the Foot of the Altar, traditional Confiteor, traditional Offertory prayers, and traditional form of administering Communion ("Corpus Domini Nostri Jesu Christi custodiat animam tuam in vitam aeternam. Amen"), various prayers in the old Mass that were excised, no more Communion in the Hand....
For avoiding confusion or for fear of casting doubt on the validity of the OF, they wouldn't allow things like: allowing the traditional cycle of readings/feast days, using the traditional form of the Roman Canon, returning the mysterium fidei to the consecration formula, etc.....
As far as things like: male-only altar servers, Latin, ad orientem, not using the chalice in distribution to the people, altar rails, no sign of peace among the people, Gregorian chant, Proper Antiphons instead of hymns, no EMHcs, etc... All of these things are optional already in the OF.
Nah, a hybridized Mass replacing both forms would be a disaster. A hybridized Mass added to the dual forms of Mass would cause confusion.