As the title suggests, I would like to see an upgrade to it, as I believe it has considerable wasted potential. 

I want the Nesser family to be more included. Like Barhan knows that Illerza is in Valencia, and we team up with him. He argues with his brothers, Sahazad and Manmehan, over whether they should imprison her or try to get rid of her, since she might do the same to Valenica as she did to Madaih. Saya pulls us aside and says she'll help us, but knowing the options presented by her brothers won't help, Illerza needed to be stopped regardless.

We go to the vault that we reach at the end of the Valencia main questline, where we find the key, either by Edan, who has joined us, or Saya, both of whom claim there should be a key hidden. We see it where we find it, through interactions, more on Black Spirits, Edana, Cartain, and her Black Spirit (via her journal entries), and some insight into Rux's creations, like Aroxxtion. There,, we meet the guardian of the vault,, who recognizes us from our previous life (our Black Spirit mocks us for not remembering the said guardian). The guardian tells us the white witch hasn't set foot in this vault since only a true Edana (like ourselves) can enter without any issue.. But it tells us that it can sense other Black Spirits (can insert if it can sense what they are feeling anything or not) but says that Illeaza is getting close to Alyaelli.

That's where we meet Kayal, who has tried to spot her but failed. He says he might not be happy with how Valenica is running, but it's still his home. Kayal helps point out that Illezra is corrupting Qabal (or the name of the Hashashin's group), and we need to stop her. We do, but she flees. Qabal reforms and Kayal, who wanted to rebuild his image, decided to take the lead (I am aware he's part of the same group as Hashashin, but I think it would be beneficial to see him in this role, allowing the group to fulfill its purpose while keeping an eye on Alyaelli). Qabal can be similar to the Mulmuks, but instead of enslaved soldiers, it is open for anyone. It the group is considered to be an elite group of solders that's main task is be ready for anything that comes out of Alyaelli.

This would give us an idea of where Illerza might go next, or a future chapter might happen, since the DEVs can drop hints of what Alyaelli is by the time we reach Kayal.

But that's how I would do it. I would like to see what you would like to see if the DEVs ever get to update the Valencia main questline. 

Im pretty sure they were working on main quest overhauls (just like balenos serendia calpheon), but question is when will we get them... 

I vaguely remember them mentioning valencia mql a few years ago. Dunno if it's been wiped from the table or not 🤷‍♀️

If one assumes they are working in order by region, they have completed Balenos, Serendia, and Calpheon.  Up next would be Mediah, then Valencia.

Fan fic is all well and good, but no thanks.