It's tough to parse all this. As Astro pointed out very early on, (don't site the generators on the seaward side of the plant) initial siting of the emergency generators in a sheltered location, along with their fuel supplies might have prevented a lot of this, although we don't really know how many critical cooling pumps and their controllers might have been compromised by the tsunami even if the generators had been high and dry.
I was pretty flabbergasted to see a US barge full of fresh water being tugged to the plant. Japan has a lot of capital resources (though not much in the way of natural ones) and it's not a stretch to think that they could have planned for tsunamis and kept some pretty large barges (loaded with chlorination equipment) at hand in case some of their coastal cities were decimated and they needed to step in until utilities were restored.
A friend of mine was tapped to help plan disaster response for US cities years back, and one critical lack that they identified was for medical care above and beyond the capacity of hospitals that try to run at near capacity to maximize income. Outfit hospital ships? What do you stock them with? Do you plan for rare contingencies? What happens for disasters in non-coastal areas (though most people seem to live near the coast and ports)?