I have always avoided Excalibur, from Wiz 6 to 7 to 8, for two reasons:1) It is heavy. In Wiz 6 weight was a huge factor, in Wiz 7 it was a big factor and in Wiz 8 it is just a factor.
2) It is two-handed. I prefer two one-handed weapons with a high instant kill chance.
With a little bit of manipulating, you can get the Light Sword from the single-sentry Bayjin chest in an evening. I have never (maybe once) gotten it from the ghosts.