The first 10 things you have listed there are entirely predictable. Indeed, the emergency procedures were designed to handle them and simply haven't coped.
They were unlucky that the tsunami was slightly worse than they had planned for, which washed away the diesel backup generators. Backups for those generators were quickly brought in, though.
OTOH, they have been very lucky that no aftershocks have caused any tsunamis (yet). If that happened right now then they are screwed.
I haven't seen any evidence of the last two occurring.
"what appears to have happened is the tsunami flooded the basements where these emergency diesel generator connections are at. So, even though they brought in mobile units, new emergency diesel generators, to hook them up to run the safety systems, the basements were flooded, where they needed to do the hook-up."
Yesterday I heard somebody who was responsible for a nuclear power plant in Europe speak on the radio (in Europe too). He said they were prepared for a malfunctioning valve, power outage etc. (predictable events) but they weren't actually prepared for the case that everything happens at once.
I wasn't saying those things were unpredictable, I meant that in combination they could result in so many different scenarios, I wonder if it's even feasible to have a plan for all of them.
The process of nuclear decay is well understood, so you can compute, given any mass of nuclear material, how much heat and for how long that mass will generate sitting in a pile by itself. You do that calculation in the presence of full moderation (all control rods inserted, below the critcial level) and without moderation (control rods out).
Now you design a thermal sink which can absorb that much heat indefinitely when either covered in soil or sitting out in free air (choose the option that has the worst heat conduction) Note that modern reactors like the Pebble Bed can't really do the whole core meltdown thing, but those that can you can design what is essentially a bucket of boron laced sand underneath them such that in the event hell breaks loose with the control rods out, the core will melt and diffuse into the sand which will drop it below critical and now you're solving for "non-critical pile turned off, how much heat from time 0 to n?"
Ok, now lets see what can cause this reactor design to cause any damage. Hmm, well its immune to anything that doesn't hit it directly and destroy the containment vessel.
So basically anything except a direct hit by an asteroid or perhaps a nuclear weapon.
Now if you look at Pebble Bed reactors they take the approach that the fuel itself is in self contained containment vessels, you can dump them out across the floor and they will cool off without doing anything else and without any radiation.
But to re-iterate what others have said, there is a security/hazard/value trade off, airplanes fall out of the sky all the time and yet people still fly, automobiles kill their occupants and yet people still drive, coal miners die trying to dig up coal and yet they keep mining.
Nuclear reactors are no different in this regard, they have a 'worst case' scenario (similar to a plane losing a wing at altitude but we're not all demanding that planes have a parachute under the seat cushion), if we only have to deal with worst case reactor scenarios during 9.0 earthquakes, I'm ok with that. I can understand if you aren't.
They were unlucky that the tsunami was slightly worse than they had planned for, which washed away the diesel backup generators. Backups for those generators were quickly brought in, though.
OTOH, they have been very lucky that no aftershocks have caused any tsunamis (yet). If that happened right now then they are screwed.
I haven't seen any evidence of the last two occurring.