Falling space debris defence systems in the Star wars universe

I would also assume that the reentry level and angle will play a factor; coming straight in would undoubtedly break apart a ship and burn up much of the smaller debris.

It's a good question and theory, BadMike; we get airplane crashes from malfunctions at least once a year, and you would think that a starship would have the same instances. I would assume that a planet such as Coruscant would have a system in place, much like how star ships have barriers to prevent air from escaping breaches in the hull and the opening of docks for ingress/egress of shuttles and smaller ships. A planetary-sized shield, I would think, would be much to massive and too expensive, but perhaps there is an orbiting ring of satallites that would help prevent it, if there were a mayday.

I would assume that since there is an ongoing battle above the skies of Coruscant, that any emergency system is either overworked, or targeted first by the Imperial forces. So if a ship went down and got sucked into the planet's gravity well, it no becomes a factor of math, physics, and blind old luck. I'd imagine that that flagship that Anikin and Obi-wan re-entered with probably scattered debris over a wide swath of city, though anything smaller than say a room was probably scorched to ashes and anything larger probably broke up and became less of a nuiscence.

I would assume that since that was more or less Coruscant's Battle of London, I would suspect that a good chunk of the population is either bunkered or shielded (like neighborhoods with a barrier on top) for such an eventuality, since I would think that the threat of a planetary bombardment would have the Republic thinking of its citizenry.

While there isn't a real canocal answer set up, I'm resorting to logic and history. A planetary system would be too much, but I could see area barriers being erected for the possibility of a burn-in.