It might not place neighbors at appreciable risk but wouldn't debris still prevent replacing the failed satellite with another one at the same precious original address?

What is the chance of getting hit by further broken pieces of that satellite and other satellites?

When calculating risk, you have to take into account how many are there and what is the chance that any will be hit. Then you have to calculate what's the chance this will happen again, etc - and only then you can calculate the risk to your own satellite.

It's true that the chance of getting hit by one broken satellite is small. But that assumes there are exactly 2 things on the orbit.

> If you have a 25 m^2 cross section in the direction of the explosion, at that distance you have a roughly 1 in 246 billion chance of any given bit of debris hitting you.

Source?

> But some debris (in particular slower pieces) will probably oscillate around the geostationary orbit giving it countless chances of hitting other satellites.

Almost all of the debris will have orbits which intersect their orbit of origin.

well while that is true only debris that has the right speed will stay there. the issue is that debris will probably have gotten some impulse that turns it orbit elliptical. that means it will slowly ratchet along geo touching it every day or so at a different place. so you get a changes every day for every piece to hit something. And even a big piece that might just have a delta of 30km/h might damage your panels on your working Sats.