I definately think the option would be nice. The range of possibilies should be based on what has been done previously, though.
I see the available starting conditions as (The ones i can think of as of End of ME2 and ignoring twists such as "rewriting the heretics backfires and causes
all geth to become 'heretics'):
A) Geth United
(Chose to rewrite)
Geth Divided
(Did not perform Loyalty Mission)C) Geth Divided, Heretics weakened
(Chose to destroy)D) Quarians United with research
(Did not reveal evidence)E) Quarians United without research
(Did not perform Loyalty Mission)F) Quarians Divided
(Revealed Evidence)G) Shepard has Geth Contact
(Recruited Legion)H) Shepard has Quarian contact
(Recruited Tali and, say, not exiled OR Kal'Reegar alive)I) Shepard has Contacts for Both
(Recruited Both + conditions)J) Shepard has no contacts
(Did not recruit either or just Tali and failed conditions)K) Shepard has enhanced Anti-Geth resources (The ME1 mission (forgot the name) OR turned Legion over to Cerberus)
Ending conditions being (Ignoring external impacts)
1:gX) Geth Destroyed
1:g-) Geth Neutral, Minor Power
1:g+) Geth Neutral, Major Power
1:G-) Geth Allies, Minor Power
1:G+) Geth Allies, Major Power
2:hX) Heretics Destroyed
2:hE) Heretics Active
3:qX) Quarians Destroyed
3:q-) Quarians Neutral, Minor Power
3:q+) Quarians Neutral, Major Power
3:Q-) Quarians Allies, Minor Power
3:Q+) Quarians Allies, Major Power
Now, i would like the activities in ME3 to determine which result occurs, but have the previous actions decide which results are possible.
For example, assuming we have the basic choices of
P) Negotiating Peace
Q) Aiding Quarians
R) Aiding Geth
(There would destorying both, but I don't know how that would play out)
Now, if we have a start of
ADG, I would want P/Q/R to lead to, say, G+hXQ+/g-hEQ+/G+hXq- (Or, if you want the all-paragon to have negative effects like I've seen people advocate, go for something like G-hXQ-/g-hEQ+/G+hXq- : you can get both weak or one of them strong. Maybe because they both agree to help, but don't trust each other enough to commit everything, or something like that)
AEG, on the other hand, would lead to G+hEQ+/g-hEQ-/G+hXQ-
While other variations such as
BDHK would lead to g-hXQ+/gXhXQ+/g+hEq- (or maybe //G-hEq-)
AFI -> G+hXQ-/g+hEQ-/G+hXq-
And so on.
At least, that is what I would
like to see.