The LCD cable is very fragile and easy to break- that's the biggie. The glass is also custom, so replacing it won't be easier either

On the upside, you could replace it with a 128x64 VFD (Noritake do an intelligent module, though it will need a 5v PSU and care to ensure it doesn't feed 5v back into the very 3.3v CPU). This would then need light kernel mods to drive it correctly.

Just don't do what I did and manage to confuse 12v (which goes to the display board for some unknown reason) and ground, as you'll toast both the receiver and the display

Hugo