I think fundamentally the issue is that when the ECML suffers a catastrophic issue like the one on Friday there simply isn't the capacity available on the MML for roughly four nine/ten-car trains per hour of ECML passengers to be accommodated on the two trains per hour of MML even with some passengers also being diverted via the WCML via Manchester and abandoning/deferring their journeys. So however you try and do it whether you try and ferry people towards 10-car services, if you try and cancel stops or insert stops, or whatever you try, the MML will become rapidly overloaded. It is often overloaded just dealing with its own passenger flows! So we can try coming up with ideas to improve the situation but there will be an element of shuffling the deck chairs on the Titanic. The MML simply doesn't have the capacity to cope with that volume of displaced passengers.
Of course in an ideal world LNER would be able to divert some of their own services from Kings Cross onto the MML but there is no easy connection (I've done it on Hull Trains, it's quite the shuffle to get from the ECML to MML!), no route knowledge (and it'd be a pain to maintain), pathing would be "interesting", and you probably only need to use it once or twice a year anyway. The slightly less mental option would be to send passengers via GA to Cambridge and onto Peterborough from there where they could intercept LNER services being turned around. But, of course, that also falls over as the link between Ely and Peterbrough is, in most hours, two trains per hour both of which are usually only two or three cars. Good luck accommodating the passengers off, say the 1600, 1603, 1630 and 1633 on that!
