Chris:
As we don't know what the problem actually is, that makes things really tough.
I'm not being facetious here, but we really do know what the problem is/was. In it's simplest form,
some of the "stuff" in the fuel tank froze and blocked path of the fuel to the engines. There may well be a number of scenarios in which this could happen so what we have to do is to prevent freezing during all of them. That means heating the fuel near the in-tank pumps. Is there a source of heat, now wasted, that could be put to good use?
Will, I share your concern about the cost of retro-fitting a change like I propose above, but how does that compare to the cost of losing a plane, not to mention crew and passengers? Fortunately, this time it was only the plane.