There's one thing that seems like such a no-brainer yet I have never seen it carried out in any game I've played. Allow blacksmiths to customize weapons and armor to the degree they can customize their characters! It seems so painfully obvious, yet would be revolutionary.

Let's say I want to craft a sword. In every game I've ever played, once I've crafted the sword, it will look like a sword. If I craft 50 more swords, they will all look like... the exact same sword. Why? The only possible way this could happen in real life is if a person only knows one way to make a sword, and does not have a single creative bone in their body. Smithing, like any creative undertaking, should result in a variety of products. Yet go onto any MMO server and the sword crafted by one person will look exactly like a sword crafted by another person. In fact, this should be literally impossible. Until the invention of machinery, it was very difficult to have two parts exactly the same. Every item made would have individual variations and flaws, and these things would make it unique. The true irony is that if you play a game like CoD that takes place AFTER the invention of machinery and interchangeable parts, you will see a variety of customization and personalization options for weapons. I find it mind-boggling that the gaming world has allowed me to customize my government-issued assault rifle, yet my smithed sword looks just like any other other sword in the world.

MMORPG's: "This is my sword, there are many like it, and this one looks like all the rest."
FPS's: "This is my rifle, it is unique and different and customized to my liking."

How does any of that make sense? It literally gives me a headache to think about it.

I'm no coder, and there might be some limitation that I don't know about, but from what I've seen it should be possible, it just never happens. I feel like ESO is in the unique position of being able to make this happen, and has enough of a record of creativity in the area of smithing to give it a shot. While there are many ways it could be enacted, I submit my own humble system.

Each sword and armor in the game consists of several parts, the number depending on the weapon/armor/item. I'll use a sword as an example. Let's say every sword in the game has four parts. The blade, the cross-guard, the handle, and the pommel. In order for me to make a sword, I need schematics (or whatever you want to call them) for each part. As a new blacksmith, I only have a single schematic for each part, so I am only able to make one type of sword.

During my travels, I discover the schematics for a new Orcish cross-guard. I can then craft a new sword that looks like the old one, however the original cross-guard has been replaced with the new Orcish one I discovered. While hardly a technological revolution, I now have a sword that looks slightly different from my first sword.

As time goes on and my character explores new areas and talks with other blacksmiths, I slowly grow my collection of weapon schematics. I am now able to choose from four different cross-guards, three different handles, and two pommels. I am still searching for a new blade schematic, though, so will have to stay with the original design on that part of my sword.

My "schematics" system could work for a variety of options and features. Perhaps there is a cult of blacksmiths that have discovered how to infuse colors into metal. If I can discover the secret, I can add a green, blue or red tinge to my sword blade (after I ALSO find the necessary materials). Or perhaps I want to make a luxurious mace for a noble. Perhaps I've heard rumors that jackalope fur (or whatever animal) has the best fur for creating a fancy looking handle. Now I must hunt the jackalope in order to have that as a handle option.

Eventually you could gain access to epic-level schematics. All the most famous swords from literature had something unique about them. Excalibur blinded the enemy when it was drawn from its scabbard. Glamdring and Sting glowed blue when orcs and goblins were nearby. A Muramasa sword was pure evil, while a Masamune sword was pure good. Up until now, an epic MMO sword is +3 to damage (boooooooring!).

Please, please, please allow for customization and personalization when smithing weapons and armor. I feel like it would revolutionize smithing in video games.

would be also cool to customize the shapes of these parts, similar way you customize your characters face in skyrim or oblivion for example.

Absolutely. I can pick fifty different possible scars on my character's face (a face I'll almost never even look at), yet I can't choose even one different option for the angle of my cross-guard? Or the amount of rust or notches on my sword blade? How does that make any sense?

EDIT: You could also incorporate a failure rate into the game. Obviously a new blacksmith will screw things up, so there should be a failure chance to each of these things. Perhaps the failures could be seen as a part of the customization. "Pass me my sword, it's the one with the unraveling handle and crooked hand-guard. *sigh*."

EDIT Pt. 2: You could even have swords that look ugly but are effective on the battlefield, and swords that look amazing but are meant for ceremonial purposes, and aren't that effective in fighting. You could include options like jewels, runes, etchings, rust, notches, spikes, etc, etc. The sky is the limit.