the issue with this, aside from getting an extra day of ice time is that, logistically, it makes little sense...
just giving you a few examples :
Let's say, Shoma goes, messes up his LP, loses many points and is no longer in the top 6.. he is out of the competition, yet he has had to fly himself and his team to the GPF at quite an expense... (even if let's say the ISU would be funding this... it's a lot of money for speculative results)...
Let's say that for instance, Rippon and Brown are ranked 5 and 6 before the FP is reskated for others like Shoma and Chan... who have a very good chance to move them down, if not both, at least one of them.... why would Rippon and Brown fly across the ocean just in the random chance that they would hold on to their GPF assignment, knowing that Shoma and Chan may only need to medal to take them out....
For any re-take of the FP... you have to understand that some skaters wouldn't go...I doubt Denis would bother knowing that he has no chance to qualify... so already, one of the seeded skater is off the hook, making Shoma's and Chan's life much easier to place in the top 3....
Not only there are a bunch of logistical and practical issues but it changes the rules and conditions for skaters.... I believe that all need to have a fair and even chance to qualify, changing rules to give extra skates which will not be done in the same conditions is unfair.... it's also unfair for someone like Misha who couldn't attend because his visa didn't come in in time... would he be given a chance to skate then? if it's postponed?
as soon as one messes with rules, it opens a huge can of worms and there are many ways where it can be unfair for others....
As far as I am concerned, the only fair thing is to move on and make the SP count for medals/points. Skaters, when they performed and competed on Friday, did their best and tried hard to place as high as possible and earn as many points as possible.. yes, some do better traditionally in the LP... but it's like Misha's visa.. it ain't happening...
I am sure if you were to ask the athletes, the first thing they would mention is that under the circumstances, it's best the event was cancelled.... I am also convinced that most of them would be fine with the SP results as final results...
Finally, as far as pairs are concerned... well... it's the same for ice dance... it actually happens quite often that in dance the top 3 are apart by only a couple points, like in WC 2014... so what's different there? THey all skated well, performing similar elements... so that's just that...
Well, having the skaters acually skate their FS - for example right pefore the GPF (i'm sure they can manage to get 1 day of rink time), is more fair than just taking the SP.
Again, look at pairs. Taking the SP score there is just like tossing a die to decide who wins.