There is Regirock as far as legendaries goes. On the subject of poison I do believe that the super effect damage against bug should be returned AND I think it would be an okay idea to add super effective damage against fighting types. Fighting types could use another weakness imo since they only currently have 2 but are also super effective toward 5 types. The only other type super effective against 5 types is ground and it has 3 weaknesses. The only justification I have for poison being super effective against fighting (outside of posion resisting fighting) would be that fighting types would move the poison through thier system faster due to the natural physical exertion is battle.