Say if I have a wizard with a mirrorimage OH special, would the +10 mirrorimage heroic skill point have an effect to the skill?
you would only be able to put it on a Pet.
putting two +5 All Skills Mythstones on your Weapons would give you +10 to all skills in use, including Procs, but not including Mythic Skills.
you could also do two +5 All Skills on the weapons and +10 Skill (Mirror Image, for example) on the Pet and have it at Skill (Mirror Image) +20.
if you get lucky and find an Eternal Pet with the Skill affix you want, and also with the +5 All Skills, you would have the Other Class Skill at +30.
on the other hand, Talent affixes on Pets from other Classes will only work for the Class they are for originally. for example, if your a Wizard had Smokebomb on their OH, and they had a Pet with Smokebomb +10 and Darkness +10 (a Rogue Skill and Talent), the Smokebomb would be cast at +10, but the Wizard would not do extra damage to enemies blinded by Smokebomb with the Darkness Talent.
Ok, I understand thank you
does weapon damage% have a cap?
not that I know of. a Legend +200% Weapon Damage on an Eternal Weapon could be +400%. and if that weapon also has a Socket, you could put an Endow Mythstone in it for another +50% Weapon Damage. and a Wizard with a weapon like that could also have Focus 40 Talent for another +100% Weapon Focus.