Mold Breaker is rather uncommon though.
I myself am a big fan of Will-O-Wisp on Weezing, as burning something that utilizes physical attacks to form its primary offense is crippled by it. However, from my own experience, people are switching to special sweepers, or just things that can manage to hit Weezing quite hard with some attacks (A Psychic-using Jirachi would be an example) and they are hurt less by Will-O-Wisp, making it harder to use. Given Weezing's quite low base HP and SpDef, it's easy for an opponent to take advantage of that weakness by bringing in a special-attacking pokemon.
If we look at Dusknoir on the other hand, it has quite some solid SpDef stats as well, so Will-O-Wisp could benefit him better, because special-based pokemon will have a just as hard job to take it down than physical pokemon, meaning switches to purely special based pokemon will be less in number than with Weezing.
I'm not denying Will-O-Wisp is a good choice on Weezing, but switches to special sweepers are quite common (at least, in my case they are) and Will-O-Wisp doesn't do much to them aside from dealing 1/8 of their max HP as damage to them each turn.
Then again, when used in tandem with Blissey, it could serve some use to downgrade the usefulness of Focus Punches or Explosions slapped on special sweepers, like Gengar to give you an example.
I myself am a big fan of Will-O-Wisp on Weezing, as burning something that utilizes physical attacks to form its primary offense is crippled by it. However, from my own experience, people are switching to special sweepers, or just things that can manage to hit Weezing quite hard with some attacks (A Psychic-using Jirachi would be an example) and they are hurt less by Will-O-Wisp, making it harder to use. Given Weezing's quite low base HP and SpDef, it's easy for an opponent to take advantage of that weakness by bringing in a special-attacking pokemon.
If we look at Dusknoir on the other hand, it has quite some solid SpDef stats as well, so Will-O-Wisp could benefit him better, because special-based pokemon will have a just as hard job to take it down than physical pokemon, meaning switches to purely special based pokemon will be less in number than with Weezing.
I'm not denying Will-O-Wisp is a good choice on Weezing, but switches to special sweepers are quite common (at least, in my case they are) and Will-O-Wisp doesn't do much to them aside from dealing 1/8 of their max HP as damage to them each turn.
Then again, when used in tandem with Blissey, it could serve some use to downgrade the usefulness of Focus Punches or Explosions slapped on special sweepers, like Gengar to give you an example.
