I was thinking about replacing the Ghostblade especially since I only used it while I was attacking towers. Especially since my cooldowns have been capped for some reason, I could probably do better with a Black cleaver of maybe even going for a trinity force. But I have not had much experience with all the items so if you had anymore suggestions they would be greatly appreciated.
Also you point on the mastery tree makes alot of sense and I will change that right away.

Interesting build and guide, I would like to say one thing though, in the utility tree you should not be taking more than one point in perseverence, you should have 3 in good hands

Looking at the benefits of perseverence:
You have 18 hp5 and mp5 at level 18. So 4% of this is .72 mp5 and hp5, for three mastery points.
So if you think about it: what is better? 1 health per 7 seconds? or 7 seconds off your late game death timer...
I have a further explanation in my Taric and Swain guides, but this is a concise version.

Also I have a questoin about ghostblade, when do you think you would activate this, i feel like pantheon is not really an autoattacking champ, and ghostblade could be replaced by something else.

Thanks Sindair for the great feedback. I am not so into runes and masteries and whatnot so I pretty much ripped them from other builds. If you can provide more insight on runes and masteries I would be very grateful. I also understand your doubts about the rageblade and I don't really much care for it as an item but the rageblade is the cheapest hybrid item in the game and the AP+AD boost it gives you is really decent. I have used the cleaver in the past and it is a very useful item but I really don't like the big ticket nature of the product. Saving up 1600 for a B.F sword is possible and rather easy late to mid game and could be fitted into this build, but i'd rather not because the AD gain over the rageblade is minimal and you lose the AP of the rageblade. But if you want, you can sell the dorans blade earlier in the game and insert the black cleaver mid-game to give you the extra AD and armor pen. This actually sounds like a good idea and I will try this in one of my game.
Again thank you for your feedback, it is highly appreciated.

http://signup.leagueoflegends.com/?ref=4dd4c9cf16a82194805972

i've got 7741 referals, i am trying to help the game creating a new champ.. create an account from this link and get level 5 and then, you can give me your opinion about ideas in this new champion. Thank You

As a Pantheon player I use as well the Bilgewater/Hextech Guns.

But there is some things that I don't understand in your build.

Like you said Pantheon is really squishy and he got no escape mechanism at all ( which is why Flash is useful).

The main problems is AP. If the Ap gave b the Hextech Guns is okay I don't understand why we should ruin 13 runes for AP at late games on long Cooldowns abilities. Also if the Guinsoo's rageblade is useful to attack faster and stacks AP how do you plan to reach an AP mage or a raged. If you use your jumps all the Ap you will stacks is really useless so you should go with a better Item like a Black Cleaver.

With this build you will have 168 Ap unstacked and 216 Ap stacked which mean 80+ damage on W and 168+ Damage On R all the times. ( I didn't take Masteries because it would be to much of a pain to calculate it)

I dont take the stacked stats because you will never suceed a Ult with Stacked AP and you will rarely jump stacxked cuz most of the time either you will be dead or they will flee Fast in front of Panth's combo.

If you still want to go with that build I think you should changes the utility tree for defense. ( 3 in MR + 1 Armor + 4 dodge + 1 Nimbless) Since you stack Dodge in your runes and this build needs to reach the enemy by other means than W Jump ( I think ? )

I m gonna try your build soon

I understand your doubts on this build and can see why you can see that AP and AS are bad stats on Pantheon but they really do change how he can be played. I would really like you to try it for yourself and see how it would work because I know that Pantheon's spells are his main source of damage. Getting you spear to do the most amount of damage is a really good way of building Pantheon but even with the low cooldown you can't use it forever. Pantheon has other assets besides his spear but instead of AD his shield hits with AP. So bolstering both sides of Pantheon's spells seems like a good idea to me even though Pantheon's AD ratio is crazy. I'm not saying I am right or you are wrong, there are just different ways of playing Pantheon and you won't know if it's any good unless you try it, or we meet on the battlefield and you see it for yourself.
Anyway, thanks for looking at my build and I appreciate your comments and your time.

This build might be awsome for jax or smthing.But not on Pantheon.

in my opinion attack speed and ability power are bad stats on pantheon

i really like this chareacter and i know that you have to get as much attack damage and armor penetration as possible