It has a weight of 1, which means it should swing really fast -- but it doesnt seem to be any faster than a regular sword. (?)

The legendary skyforge axe I have DOES swing faster than a normal axe, so it is better than the legendary Ebony I gave to Lydia (I think.)

If I upgrade the Ghost Blade to legendary (assuming I can) will it be better than the skyforge axe?

It takes 3x ectoplasm to upgrade -- no idea where i will get that. And im not sure if I will get the same "legendary" smithing bonus because its not steel, orcish, or dwarvish.

?

Its so so. You cant get that much out of it because its not part of a smithing tree, but it can be handy for high armor targets (Eg bandit leaders if a mage).

ok thanks. I just read the wiki for this item and my ghost sword is like 25 damage, the one in the wiki is 9. So I assume this scales to the level of the character when he obtains it. Meaning its not going to be that special.

It doesnt swing as fast as a dagger.

wrong, its just based on base damage from when your one handed skill is att its lowest, which is 15 i belive, then it does 9 damage and thats why yours do more since you have higher skill and perks to go along with it. Its not scaled

It's at best a situational weapon. It's base damage isn't that great, even when improved. But it doesn't lose all that much damage against high armor targets. I think you still come out a lot better with a well improved crafted 1h weapon with some sort of damaging enchant on it. The reduction in armor mitigation will not equal or surpass 20+ points of fire or shock damage on top of the weapon damage.