Uhm, there are I think at least a few other sci-fic universes which have ships capable of destroying entire stars, compare that with the sun crusher.
For example, Halo Wars' "Halo Array" is capable of destroying all sentinent life in the galaxy when activated - and yet it's not even included in that chart. There are craptons of powerful ships aside from SW and ST.
Another example is the Sathanas juggernaut from FreeSpace II. One of these is capable of destroying a planet, and a fleet of 80 can annihilate a sun in a couple of minutes by tearing apart a subspace field (according to wikipedia).
So my conclusion is, Star Wars has pretty much of the biggest ships in the entire history of Science Fiction (DS II), but not necessarilly the most powerful. The Sathanas is just 6 kilometers and yet it could probably destroy a planet.
http://en.wikipedia.org/wiki/Planet_killer