Could we just keep the requirements pretty much the same as they are now? Three jumping passes, two spins, one or two spirals, one or two footworks? The scoring would be set up in such a way as to "expect" the skaters to do three different jumps in each of the two programs. Not necessarily, but strongly favored in the scoring system.
So both programs would have the same requirements (as the current short program) but skaters would be expected to show different skills in each?
Just for fun, I came up with a couple of options.
Least restrictive:
Every skater gets 14 elements to spread across two 3-minute programs:
6-8 jump passes (may include one small-jump sequence with levels)
3-5 spins
1-2 step sequences
1-2 miscellaneous (spiral sequence, field moves sequence, school figures variation)
Basically the limits and requirements are the same as in the current long program, with a few extra elements allowed, and they can be spread across the two programs any way the skater chooses. The tech panel would keep track of what was done in the first program and consider those slots already filled so skaters would have to show different skills in the second program.
The most unbalanced approach would be to put all the jumps and spins in one program and include only the sequences and uncaptured pure skating in the other program. That would be allowed and could be a valid strategy if planned intelligently with the music and choreography for each program. Most skaters would probably opt for 4 jumps, 2 spins, and 1 sequence in each program or differ from that by only 1 element.
Most restrictive:
Both programs would be technical programs, and shorter than the current long program, with required elements that would force every skater to show a good balance of technical skills expected of senior-level skaters. Maybe the rules specify which elements must go in program 1 and which in program 2, or maybe the skater just has a list of required elements that must be spread across the two programs in a template like 4 jumps, 2 spins, 1 sequence per program but the exact distribution is the skater's choice.
*Solo axel jump (double or triple)
*Solo lutz (double, triple, or quad)
*Solo salchow or loop jump immediately preceded by steps or other connecting moves (double, triple, or quad)
*Solo toe loop or flip jump immediately preceded by steps or other connecting moves (double, triple, or quad)
*Any other solo jump not one of the above
*Jump combination consisting of any two jumps of 2 or more revolutions
*Another jump combination of any two or three jumps, at least one of which must be triple
*Sequence of 3 or more jumps of no more than 2 revolutions each, or may include one double axel or one triple not already executed, with no more than one step or turn between jumps, level features to be determined
(Zayak rule applies to repeated triples and quads)
*Forward camel or layback spin, no change of foot, no catch-foot positions but other features allowed
*Spin with all 3 basic positions (may fly, may change feet)
*Spin with backward entry (may change feet and/or position)
*Spin with flying entry (may change feet and/or position)
(no 2 spins may have the same code)
*Step sequence, which must meet the requirements for “simple variety of steps and turns” (if not, the tech panel will flag it and judges must give negative GOE; if yes and there’s also at least one other feature, then it will earn a higher level)
*Field Moves sequence which must include at least 1 spiral with the free leg at hip height or above; may include other spirals and/or choice of spread eagle, Ina Bauer, shoot-the-duck/hydroblading positions; features to be determined
Or -- one of the programs might give extra rewards to the "small jump sequence"

, split jumps, weird wally+bunny hop combinations, and also to moves in the field like ina bauers, spread eagles, Charlottes, etc.
In fact, the more I think about it, the two programs could be called the short technical program and the short free program.
So maybe the short technical program (STP) would be similar to the SP in the 1980s, or to the current junior SP, with specified elements that rotate each year.
And the short free program (SFP) could be ~3 minutes, maximum 8 or maybe 9 elements, which could be exactly the same elements as in the tech program plus an extra, or completely different elements, or some repeats and some new. The Scale of Values would list all the possible elements that gain points, SFP rules would put caps of maybe 5 jump elements, 3 jump combos, 2 repeated jumps, 3 spins (each with different codes), but otherwise the skater could mix and match at will.
That wouldn't allow any way to penalize skaters for repeating the exact same content in both programs or reward them for showing variety across programs, though.
And if you want variety between programs in music and choreo style, how would that be enforced or encouraged?