However I think we can have a really good stab at the proposals based on what we now know e.g. that the programs will have equal weight, and that the split is 40/60 in each.
The split between TES and PCS. Which will always have to be approximate as it is now.
Part of the current problem is that the PCS factors were based on the kind of technical content that was common ca. 2003. In recent years jump content has exploded so much that the good jumpers are earning much more in TES than in PCS, even if they also excel at PCS skills.
Which means that at the very least the PCS factors need to be reconsidered. But if the idea is to have one competition phase that is specifically designed to emphasize the kinds of skills that happen between technical elements, then the program requirements for that phase also need to be revised, perhaps significantly.
If the SP is to be the basis of the Artistic program
The ISU has not said that will be the case.
If they want it to be 3:30 in length, I assume they will decide how many jumping passes they want it to have, how many spin slots, how many step sequences (leveled or not) or other choreo-type elements, figure out likely maximum scores with that program structure, and assign PCS factors accordingly.
There's no need to start with the current short program as a template. They could look at something like the Medal Winners Open requirements (which do have the same number of elements as current short programs) or the Peggy Fleming trophy or various pro or pro-am formats from before the IJS era.
As far as I know they're still thinking about keeping the current five components, but if that number were to change then the actual factors would also need to change.
I don't know what's planned for the technical program, but keep in mind that the current junior ladies' freeskate is 3:30 and the only difference in content between that and the 4:00 senior programs is the choreo sequence, which presumably would not be included.
The more PCS categories there are, the more the skaters who can max them out do benefit,
Again, it depends on what the factors are. If there are 3 PCS categories each with a factor of 2.0 (maximum score 60), skaters who excel in PCS could earn more than if there are 5 categories each with a factor of 1.0 (maximum score 50).
Of the PCS categories some lend themselves to being measured quantifiably, when they are split out (for example composition can be a function of ice coverage as calculated from an ice map at least in part), skating skill and transition also are quantifiable.
In theory, individual criteria of these components could be measured or counted quantifiably. E.g., ice speed, ice coverage, numbers of turns in each direction, amount of time spent on one foot or in each direction, numbers of different kinds of transitional moves, etc.
But they would need to be split out.
And first someone needs to come up with practical and cost-effective methods for measuring these things in a variety of different rink configurations, availability of extra officials, etc.
Meanwhile some aspects of these components remain qualitative by nature. You're never going to measure objectively whether someone has "soft knees," but that is one of the defining qualities of good skating quality.