If a sensibly reduced timetable were introduced, with a blanket ESR and DMU operation where possible - perhaps taking a AWC approach and splitting longer runs into shorter segments, do you think total cancellations would still have been greater (taking into account potential units out of place, crew etc the following day)?
Replacing EMU services with DMUs is fraught with practical difficulties because many (but not all) Scotrail electric trains are Driver Only, whereas all DMUs require a Guard as well, so for example running Ayrshire or Inverclyde services with DMUs would be next to impossible. It could perhaps be done for say an Edinburgh/Glasgow service, assuming that the Drivers and Guards have retained competency for DMUs, although course every DMU taken to run vice EMU is one less DMU for their booked services. In any case what would result would be a greatly reduced service on those routes which were served, and still with the possibility of disruption due to line blockages, and wires down which do not power DMUs but still impede their progress.
As regard splitting services into self-contained segments, I am not sure there are actually many Scotrail services where that would be practical, maybe just the Edinbugh/Glasgow to Aberdeen/Inverness routes, with a split at Perth or Dundee, although if crews work their train throughout it would not help anyway.
I do still think that while undoubtedly drastic, and disruptive to many passengers' journeys, Scotrail's decision did result in much less overall disruption, and I wish a similar policy had been introduced on some of the horrendous severe weather days I experienced at work !